424B5 1 form424b5.htm 424B5

Filed pursuant to Rule 424(b)(5)

Registration No. 333-291981

PROSPECTUS SUPPLEMENT

(To Prospectus dated March 26, 2026)

18,000,000 Shares

Lucid Diagnostics Inc.

Common Stock

We are offering 18,000,000 shares of our common stock pursuant to this prospectus supplement and the accompanying base prospectus.

Our common stock is listed for trading on the Capital Market of the Nasdaq Stock Market, or “Nasdaq,” under the symbol “LUCD.” On April 22, 2026, the last reported sales price of our common stock was $1.31 per share.

	Per Share		Total
Offering price	$	1.00	$	18,000,000
Underwriting discount to be paid to the underwriters by us⁽¹⁾	$	0.06	$	1,080,000
Proceeds to us, before expenses	$	0.94	$	16,920,000

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We have also agreed to reimburse the underwriters for certain out-of-pocket accountable expenses incurred by them in connection with this offering, up to a maximum of $75,000. See “Underwriting” for additional information.

Investing in our common stock involves a high degree of risk. See the section entitled “Risk Factors” beginning on page S-6 of this prospectus supplement and in the documents incorporated by reference herein and in the accompanying base prospectus for a discussion of information that should be considered in connection with an investment in our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying base prospectus. Any representation to the contrary is a criminal offense.

Delivery of the shares is expected to be made against payment therefore on or about April 24, 2026.

Joint Bookrunners

Canaccord Genuity

BTIG

The date of this prospectus supplement is April 23, 2026.

TABLE OF CONTENTS

PROSPECTUS SUPPLEMENT

ABOUT THIS PROSPECTUS SUPPLEMENT	S-ii
MARKET AND INDUSTRY DATA	S-ii
TRADEMARKS	S-iii
NOTE ON FORWARD-LOOKING STATEMENTS AND RISK FACTOR SUMMARY	S-iii
GLOSSARY	S-iv
PROSPECTUS SUPPLEMENT SUMMARY	S-1
THE OFFERING	S-5
RISK FACTORS	S-6
USE OF PROCEEDS	S-10
CAPITALIZATION	S-11
DILUTION	S-12
DESCRIPTION OF COMMON STOCK	S-13
UNDERWRITING	S-14
LEGAL MATTERS	S-16
EXPERTS	S-16
WHERE YOU CAN FIND MORE INFORMATION	S-16
INFORMATION INCORPORATED BY REFERENCE	S-17

PROSPECTUS

ABOUT THIS PROSPECTUS	ii
MARKET AND INDUSTRY DATA	ii
TRADEMARKS	iii
NOTE ON FORWARD-LOOKING STATEMENTS AND RISK FACTOR SUMMARY	iii
GLOSSARY	iv
PROSPECTUS SUMMARY	1
RISK FACTORS	5
USE OF PROCEEDS	5
DESCRIPTION OF CAPITAL STOCK	6
DESCRIPTION OF DEBT SECURITIES	11
DESCRIPTION OF WARRANTS	17
DESCRIPTION OF THE UNITS	18
PLAN OF DISTRIBUTION OF SECURITIES	19
LEGAL MATTERS	22
EXPERTS	22
WHERE YOU CAN FIND MORE INFORMATION	22
INFORMATION INCORPORATED BY REFERENCE	23

S-i

ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying base prospectus are part of a registration statement under the Securities Act on Form S-3 that we filed with the Securities and Exchange Commission, or the “SEC,” using a “shelf” registration process. Under this shelf process, we may, from time to time, sell or issue any of the combination of securities described in the accompanying base prospectus in one or more offerings with a maximum aggregate offering price of up to $175,000,000.

The base prospectus provides you with a general description of the securities we may offer under the registration statement. This prospectus supplement provides specific details regarding this offering of 18,000,000 shares of our common stock. Generally, when we refer only to the “prospectus,” we are referring to both parts combined. This prospectus supplement contains specific information about the terms of this offering. This prospectus supplement may also add, update or change information contained in the accompanying base prospectus. If there is any inconsistency between the information in this prospectus supplement and the accompanying base prospectus, you should rely on the information in this prospectus supplement. You should read both this prospectus supplement and the accompanying base prospectus, together with the additional information described below under the heading “Where You Can Find More Information” and “Information Incorporated by Reference.”

You should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying base prospectus and in any issuer free writing prospectus relating to this offering. We have not authorized anyone to provide you with different information and, if provided, such information or representations must not be relied upon as having been authorized by us. Neither this prospectus supplement nor the accompanying base prospectus nor any issuer free writing prospectus shall constitute an offer to sell or a solicitation of an offer to buy offered securities in any jurisdiction in which it is unlawful for such person to make such an offering or solicitation. This prospectus supplement and the accompanying base prospectus and any issuer free writing prospectus do not contain all of the information included in the registration statement. For a more complete understanding of the offering of the securities, you should refer to the registration statement, including its exhibits.

You should not assume that the information appearing in this prospectus supplement or the information appearing in the accompanying base prospectus is accurate as of any date other than the date on the front cover of this prospectus supplement or the accompanying base prospectus, respectively. You should not assume that the information contained in the documents incorporated by reference in this prospectus supplement or the accompanying base prospectus, or in any issuer free writing prospectus, is accurate as of any date other than the respective dates of those documents. Our business, financial condition, results of operations, and prospects may have changed since that date.

Unless otherwise indicated or unless the context otherwise requires, all references in this prospectus supplement to “Lucid Diagnostics,” “Lucid,” the “Company,” and “we,” “us” and “our” refer to Lucid Diagnostics Inc., a Delaware corporation, and its subsidiaries.

MARKET AND INDUSTRY DATA

We obtained the market, industry and competitive position data used throughout this prospectus and the documents incorporated by reference in this prospectus from our own internal estimates and research, as well as from independent market research, industry and general publications and surveys, governmental agencies and publicly available information in addition to research, surveys and studies conducted by third parties. Internal estimates are derived from publicly available information released by industry analysts and third-party sources, our internal research and our industry experience, and are based on assumptions made by us based on such data and our knowledge of our industry and market, which we believe to be reasonable. In some cases, we do not expressly refer to the sources from which this data is derived. In that regard, when we refer to one or more sources of this type of data in any paragraph, you should assume that other data of this type appearing in the same paragraph is derived from the same sources, unless otherwise expressly stated or the context otherwise requires. In addition, while we believe the industry, market and competitive position data included or incorporated by reference in this prospectus are reliable and based on reasonable assumptions, such data involve risks and uncertainties and are subject to change based on various factors, including those discussed in the section titled “Risk Factors.” These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties or by us.

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TRADEMARKS

We have proprietary rights to trademarks used in this prospectus supplement and the accompanying base prospectus and in the documents incorporated by reference in this prospectus supplement and the accompanying base prospectus, including Lucid Diagnostics™, EsoGuard®, EsoCheck® and Collect+Protect™. Solely for our convenience, trademarks and trade names referred to in this prospectus supplement and the accompanying base prospectus, and in the documents incorporated by reference in this prospectus supplement and the accompanying base prospectus, may appear without the “®” or “™” symbols, but such references are not intended to indicate, in any way, that we will not assert, to the fullest extent possible under applicable law, our rights or the rights to these trademarks and trade names. We do not intend our use or display of other companies’ trade names, trademarks, or service marks to imply a relationship with, or endorsement or sponsorship of us by, any other companies. Each trademark, trade name, or service mark of any other company appearing in this prospectus supplement and the accompanying base prospectus, and in the documents incorporated by reference in this prospectus supplement and the accompanying base prospectus, is the property of its respective holder.

NOTE ON FORWARD-LOOKING STATEMENTS AND RISK FACTOR SUMMARY

This prospectus supplement contains “forward-looking statements” within the meaning of Section 27A of the Securities Act and Section 21E of the Securities Exchange Act of 1934, as amended, or the “Exchange Act.” The statements contained in this prospectus supplement and in the documents incorporated by reference in this prospectus supplement that are not purely historical are forward-looking statements. Forward-looking statements include, but are not limited to, statements regarding expectations, hopes, beliefs, intentions or strategies regarding the future, such as our estimates regarding expenses, future revenue, capital requirements and needs for additional financing and our expectations regarding the time during which we will be an emerging growth company under the JOBS Act. In addition, any statements that refer to projections, forecasts or other characterizations of future events or circumstances, including any underlying assumptions, are forward-looking statements. The words “anticipates,” “believes,” “continues,” “could,” “estimates,” “expects,” “intends,” “may,” “might,” “plans,” “possible,” “potential,” “predicts,” “projects,” “should,” “would” and the negative of these terms and similar expressions may identify forward-looking statements, but the absence of these words does not mean that a statement is not forward-looking.

The forward-looking statements contained in this prospectus supplement and in the documents incorporated by reference in this prospectus supplement are based on our current expectations and beliefs concerning future results, developments and their potential effects on us and on a number of assumptions. Although we believe that our current expectations, beliefs and assumptions are reasonable, there can be no assurance that they will prove correct. The forward-looking statements involve a number of risks and uncertainties (some of which are beyond our control) that may cause actual results, developments and their effects on us to be materially different from those expressed or implied by these forward-looking statements. These risks and uncertainties include, but are not limited to, those factors incorporated by reference or described in “Risk Factors,” including the following:

	●	our limited operating history;

	●	our financial performance, including our ability to generate revenue;

	●	our ability to obtain regulatory approval for the commercialization of our products;

	●	the risk that the FDA will cease to exercise enforcement discretion with respect to LDTs, like EsoGuard;

	●	our ability of our products to achieve market acceptance;

	●	our success in retaining or recruiting, or changes required in, our officers, key employees or directors;

	●	our potential ability to obtain additional financing when and if needed;

	●	our ability to protect our intellectual property;

	●	our ability to complete strategic acquisitions;

	●	our ability to manage growth and integrate acquired operations;

	●	the potential liquidity and trading of our securities;

	●	our regulatory and operational risks;

	●	cybersecurity risks;

	●	risks related to health-related emergencies;

	●	risks related to our relationship with PAVmed; and

	●	our estimates regarding expenses, future revenue, capital requirements and needs for additional financing.

Should one or more of these risks or uncertainties materialize, or should any of our expectations, beliefs or assumptions otherwise prove incorrect, actual results, developments and their effects on us may vary in material respects from those projected in these forward-looking statements. Accordingly, you should not rely on these forward-looking statements. We do not undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws.

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GLOSSARY

Unless otherwise stated in this prospectus supplement:

	●	“510(k)” refers to a premarket notification, submitted to the FDA by a manufacturer pursuant to section 510(k) of the FDCA and 21 CFR § 807 subpart E, of its intent to market a non-exempt Class I or Class II medical device intended for human use, for which a PMA application is not required, to demonstrate that the device to be marketed is as safe and effective, that is, substantially equivalent to, a legally marketed device, commonly known as a “predicate”; and “510(k) clearance” refers to a determination by FDA under 21 CFR § 807.100 that a medical device has been found to be substantially equivalent to a legally marketed predicate device and can be marketed in the U.S.

	●	“BE” refers to Barrett’s Esophagus, an esophageal precancer and complication of GERD in which surface cells lining the lower esophagus undergo precancerous metaplastic or dysplastic transformation from repeated exposure to stomach fluid, including acid, refluxing into the lower esophagus. BE can be nondysplastic or dysplastic. In nondysplastic BE, or “NDBE,” there is no dysplasia. In dysplastic BE, there is dysplasia, which can be early, low-grade dysplasia, or “LGD,” or advanced, high-grade dysplasia, or “HGD.”

	●	“CE Mark” refers to “Conformité Européenne” Mark, a mark indicating that a product such as a medical device conforms to the essential requirements of the relevant European directive and may be marketed in European Economic Area (the European Union, Norway, Iceland, and Lichtenstein), Switzerland, and, until July 1, 2023, the United Kingdom; for medical devices and in vitro devices the relevant directives had been Medical Device Directive 93/42/EEC and In-Vitro Diagnostic Medical Devices Directive 98/79/EC, respectively, but have been or will soon be replaced by Regulation (EU) 2017/745 and Regulation (EU) 2017/746, respectively.

	●	“CLIA” refers to the Clinical Laboratory Improvement Amendments of 1988 and associated regulations set forth in 42 CFR § 493, through which CMS regulates all non-research laboratory testing performed on humans in the U.S., including LDTs.

	●	“CMS” refers to the U.S. Center for Medicare and Medicaid Services.

	●	“EAC” refers to esophageal adenocarcinoma, the most common and highly lethal form of esophageal cancer which universally arises from BE.

	●	“EGD” refers to esophagogastroduodenoscopy, or upper gastrointestinal endoscopy, an invasive diagnostic or therapeutic procedure typically performed in an ambulatory endoscopy or surgery center under intravenous anesthesia, which allows the operator to visualize, sample and in some circumstances treat conditions of the esophagus, stomach, or duodenum.

	●	“FDA” refers to the U.S. Food and Drug Administration.

	●	“FDCA” refers to the U.S. Food, Drug, and Cosmetic Act as codified in 21 CFR.

	●	“GERD” refers to gastroesophageal reflux disease, commonly known as chronic heart burn, acid reflux, or just reflux, a symptomatic or asymptomatic pathologic condition where dysfunction of the muscular valve between the stomach and esophagus allows stomach fluid, including acid, to inappropriately reflux into the lower esophagus.

	●	“IVD” refers to an in vitro diagnostic product, defined by FDA as a reagent, instrument, or system intended for use in diagnosis of disease or other conditions; such a product is intended for use in the collection, preparation, and examination of specimens take from the human body and is a device as defined in the FDCA.

	●	“LDT” or “laboratory developed test” refers to a diagnostic test, defined by FDA as “an IVD that is intended for clinical use and designed, manufactured and used within a single laboratory,” which is generally subject only to self-certification of analytical validity under the CMS CLIA program; FDA had historically exercised enforcement discretion with regard to premarket review of LDTs but intends to phase out this approach as described in “Prospectus Summary—Recent Developments” below.

	●	“PAVmed” refers to PAVmed Inc., our parent company.

	●	“PMA” refers to premarket approval, the most stringent FDA premarket medical device scientific and regulatory review process, codified in 21 CFR § 814, which, due to the risk associated with Class III devices, requires sufficient valid scientific evidence in addition to general and special controls to assure that it is safe and effective for its intended use(s).

S-iv

PROSPECTUS SUPPLEMENT SUMMARY

This summary contains basic information about us and our business but does not contain all of the information that is important to your investment decision. You should read this summary together with the more detailed information contained elsewhere in this prospectus supplement and the accompanying base prospectus and the documents incorporated herein and therein by reference before making an investment decision. Investors should carefully consider the information set forth under the caption “Risk Factors” appearing elsewhere in this prospectus supplement, including those incorporated by reference herein.

Our Company

We are a commercial-stage, cancer prevention medical diagnostics technology company focused on the millions of patients with GERD, who are at risk of developing esophageal precancer and cancer, specifically highly lethal EAC.

We believe that our flagship product, the EsoGuard Esophageal DNA Test, performed on samples collected with the EsoCheck Esophageal Cell Collection Device, constitutes the first and only commercially available diagnostic test capable of serving as a widespread tool with the goal of preventing EAC deaths through the early detection of esophageal precancer in at-risk GERD patients.

EsoGuard is a bisulfite-converted targeted next-generation sequencing (NGS) DNA assay performed on surface esophageal cells collected with EsoCheck. It quantifies methylation at 31 sites on two genes, Vimentin (VIM) and Cyclin A1 (CCNA1). Analytical validation tests of EsoGuard demonstrated approximately 97% analytical sensitivity, 95% analytical specificity, 98% analytical accuracy, and 100% inter-assay and intra-assay precision. Performance characteristics of the EsoGuard test have been evaluated in two case-control studies and two prospective, single-arm cohort studies. Both cohort studies were designed as “screening” studies, enrolling patients from the intended-use population. In these screening settings, EsoGuard demonstrated a positive predictive value (PPV) of 30–33% and a negative predictive value (NPV) of 99% for the detection of BE and EAC.

EsoCheck is an FDA 510(k) and CE Mark cleared noninvasive swallowable balloon capsule catheter device capable of sampling surface esophageal cells in a less than two-minute office procedure. It consists of a vitamin pill-sized rigid plastic capsule tethered to a thin silicone catheter from which a soft silicone balloon with textured ridges emerges to gently swab surface esophageal cells. When suction is applied, the balloon and sampled cells are pulled into the capsule, protecting them from contamination and dilution by cells outside of the targeted region during device withdrawal. We believe this proprietary Collect+Protect™ technology makes EsoCheck the only noninvasive esophageal cell collection device capable of such anatomically targeted and protected sampling.

EsoGuard and EsoCheck are based on patented technology licensed by Lucid from Case Western Reserve University, or “CWRU.” EsoGuard and EsoCheck have been developed to provide an accurate, non-invasive, patient-friendly test for the early detection of EAC and BE, including dysplastic BE and related precursors to EAC in patients with GERD.

Recent Developments

Medicare Coverage

In November 2024, we submitted to MolDx our complete clinical evidence package in support of a request for reconsideration of the non-coverage language in the local coverage determination, or “LCD,” to secure Medicare coverage for EsoGuard. The EsoGuard clinical evidence package included six new peer-reviewed publications: three clinical validation studies (two in the intended use population, one case control), two clinical utility studies, and one analytical validation study. The current LCD provides clear coverage criteria consistent with the American College of Gastroenterology guidelines for esophageal precancer testing. The package was submitted as part of a request for reconsideration of the non-coverage language in the LCD to secure Medicare coverage for EsoGuard.

As part of the LCD reconsideration process, MolDx-participating Medicare Administrative Contractors convened a Contractor Advisory Committee Meeting regarding the LCD on September 4, 2025. At the meeting, eleven experts, including physicians across multiple specialties (GI, primary care, pathology), major society guideline co-authors (American College of Gastroenterology, American Gastroenterological Association) and industry leaders (American Foregut Society, American Society for Gastrointestinal Endoscopy), participated in this extensive discussion of the unmet clinical need with respect to early detection of esophageal precancer and the strength of the EsoGuard clinical validity and clinical utility data.

S-1

Department of Veteran Affairs

On January 21, 2026, we announced that we had been awarded a contract by the U.S. Department of Veterans Affairs (VA) for our EsoGuard Esophageal DNA Test, expanding access to esophageal precancer testing across the nation’s largest integrated healthcare system, which serves more than nine million enrolled veterans annually.

Real-World Experience Data

In December 2025, we announced results from an 18-month real-world experience evaluating the EsoGuard and EsoCheck in approximately 12,000 patients. The analysis demonstrated high technical success rates, rapid procedure times, and appropriate physician utilization in routine clinical practice, consistent with previously reported clinical studies. The data are currently under peer review for publication.

Board Appointment

Effective September 22, 2025, our board of directors appointed John R. Palumbo as a Class B director. Mr. Palumbo was designated for appointment by certain of the holders of our Senior Convertible Notes issued in November 2024, or the “2024 Convertible Notes.”

Clinical Study Publications

In September 2025, a case series published in Gastroenterology & Hepatology highlighted four real-world cases in which EsoGuard facilitated the timely detection of either HGD or intramucosal carcinoma (IMC; T1a esophageal adenocarcinoma). In all four cases, the patients had no prior history of EGD, including one individual who had previously declined multiple EGD referrals. Following positive in-office EsoGuard results, each patient proceeded with endoscopic evaluation, which led to successful identification and eradication of disease in all cases. This case series underscores both the clinical utility of EsoGuard in detecting early-stage neoplasia and the ease with which the test can be integrated into standard office workflows to enhance screening uptake and early disease detection.

Corporate Information

We are a Delaware corporation formed on May 8, 2018 and are a subsidiary of PAVmed. Our executive offices are located at 360 Madison Avenue, 25th Floor, New York, NY 10017, and our telephone number is (917) 813-1828. Our corporate website is www.luciddx.com. The information contained on or that can be accessed through our website is not incorporated by reference into this prospectus and you should not consider information on our website to be part of this prospectus or in deciding whether to purchase our securities.

Implications of Being an Emerging Growth Company

We are an “emerging growth company” within the meaning of the federal securities laws. For as long as we are an emerging growth company, we will not be required to comply with certain disclosure and other obligations that are applicable to public companies that are not emerging growth companies, including not being required to comply with the auditor attestation requirements of Section 404 of the Sarbanes-Oxley Act of 2002, as amended, the “Sarbanes-Oxley Act,” being able to take advantage of reduced disclosure obligations regarding executive compensation in our periodic reports and proxy statements, and being exempt from the requirements of holding a nonbinding advisory vote on executive compensation and stockholder approval of any golden parachute payments not previously approved. We intend to take advantage of these reduced disclosure and other obligations until we are no longer an emerging growth company.

In addition, Section 107 of the Jumpstart Our Business Startups Act, the “JOBS Act,” provides that an emerging growth company can use the extended transition period provided in Section 7(a)(2)(B) of the Securities Act for complying with new or revised accounting standards. This permits an emerging growth company to delay the adoption of certain accounting standards until those standards would otherwise apply to private companies. We have elected to use this extended transition period for complying with new or revised financial accounting standards.

We may remain an emerging growth company for up to five years (through December 31, 2026), although we will lose that status as of the last day of the fiscal year in which we have more than $1.235 billion of revenues, have more than $700.0 million in market value of our common stock held by non-affiliates (assessed as of the most recently completed second quarter), or if we issue more than $1.0 billion of non-convertible debt over a three-year period.

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Risk Factor Summary

Our business is subject to numerous risks, as more fully described in the section entitled “Risk Factors” immediately following this prospectus summary and in Item 1A, “Risk Factors,” in our annual report on Form 10-K, which is incorporated herein by reference. We may be unable, for many reasons, including those that are beyond our control, to implement our current business strategy and to become profitable. Those risks and uncertainties include the following:

Risks Associated with Our Financial Condition

	●	We have incurred operating losses since our inception and may not be able to achieve profitability.

	●	We have concluded there is substantial doubt of our ability to continue as a going concern and our independent registered public accounting firm’s report on our financial statements contains an explanatory paragraph describing our ability to continue as a going concern.

	●	To raise capital, we have issued a significant amount of convertible securities under which we expect to issue a correspondingly significant amount of shares of our common stock upon conversion thereof. In addition, we may issue shares of our capital stock or debt securities in the future in order to raise capital to fund our operations. All of the foregoing would dilute the equity interest of our stockholders and might cause a change in control of our ownership.

	●	We expect to need additional capital funding, which may be compounded by our obligations to our parent company, PAVmed, which requires its own additional capital funding.

	●	Our quarterly operating results could be subject to significant fluctuation, which could increase the volatility of our stock price and cause losses to our stockholders.

	●	Servicing our indebtedness may require a significant amount of cash, and the restrictive covenants contained in our indebtedness could adversely affect our business plan, liquidity, financial condition, and results of operations.

Risks Associated with Our Business

	●	Since we have a limited operating history, and have not generated any significant revenues to date, you will have little basis upon which to evaluate our ability to achieve our business objective.

	●	The markets in which we operate are attractive and other companies or institutions may develop and market novel or improved technologies, which may make the EsoGuard or EsoCheck technologies less competitive or obsolete.

	●	We expect to derive substantially all of our revenues from the EsoGuard and EsoCheck products.

	●	We are highly dependent on our license agreement with CWRU, the termination of which would prevent us from commercializing our products, and which imposes significant obligations on us.

	●	Our products may never achieve market acceptance.

	●	Recommendations in published clinical practice guidelines issued by various organizations, including professional societies and federal agencies may significantly affect payors’ willingness to cover, and physicians’ willingness to prescribe, our products and services.

Risks Associated with Healthcare Regulation, Billing and Reimbursement, and Product Safety and Effectiveness

	●	If private or governmental third-party payors do not maintain reimbursement for our products at adequate reimbursement rates, we may be unable to successfully commercialize our products which would limit or slow our revenue generation and likely have a material adverse effect on our business.

	●	If our clinical studies do not satisfy providers, payors, patients and others as to the reliability and performance of our EsoGuard test and the EsoCheck device, or any other product or service we may develop and seek to commercialize, we may experience reluctance or refusal on the part of physicians to order, and third-party payors to pay for, such test.

	●	Clinical laboratories and medical diagnostic companies are subject to extensive and frequently changing federal, state, and local laws. We could be subject to significant fines and penalties if we fail (or if our prior unrelated third-party laboratory partner previously failed) to comply with these laws and regulations.

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	●	Many aspects of our business, beyond the specific elements described above, are subject to complex, intertwined, costly and/or burdensome federal health care laws and regulations which may open to interpretation and be subject to varying levels of discretionary enforcement. If we fail to comply with these laws and regulations, we could face substantial penalties and our business, operations and financial condition could be adversely affected.

	●	Due to billing complexities in the diagnostic and laboratory service industry, we may not be able to collect payment for the EsoGuard tests we perform.

	●	The results of our clinical trials may not support our product candidate claims or may result in the discovery of adverse side effects.

Risks Associated with Our Intellectual Property and Technology Infrastructure

	●	We may not be able to protect or enforce the intellectual property rights for the technology used in, or expected to be used in, our products, which could impair our competitive position.

	●	We may be subject to intellectual property infringement claims by third parties which could be costly to defend, divert management’s attention and resources, and may result in liability.

	●	Competitors may violate the intellectual property rights for the technology used in, or expected to be used in, our products, and we may bring litigation to protect and enforce our intellectual property rights, which may result in substantial expense and may divert our attention from implementing our business strategy.

Risks Associated with Our Relationship with PAVmed

	●	PAVmed holds more voting stock than any of our other shareholders and thus it (or any successor to its stake in us), may have significant influence over certain actions requiring a stockholder vote.

	●	As a result of the exercise by the holder of PAVmed’s convertible debt and preferred stock of its rights under the agreements governing those instruments, such holder could acquire voting control of us.

	●	Certain conflicts of interest may arise between us and our affiliated companies, including PAVmed, and in some cases we have waived certain rights with respect thereto.

Risks Associated with Ownership of Our Common Stock

	●	Nasdaq may in the future delist our common stock, which could limit investors’ ability to make transactions in our securities and subject us to additional trading restrictions.

	●	Our stock price may be volatile, and holders of our common stock could incur substantial losses.

	●	Our outstanding options, convertible preferred stock and convertible notes, along with the potential issuance of shares under our equity compensation plans and other arrangements, may have an adverse effect on the market price of our common stock.

	●	We do not expect to pay any dividends in the foreseeable future.

Risks Associated with the Offering

	●	You will experience immediate and substantial dilution in the net tangible book value per share of the common stock you purchase.

	●	This offering could cause the price of our common stock to decline.

	●	Our management will have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

	●	Even after giving effect to this offering, we expect to require additional capital funding, which may not be available on acceptable terms, or at all, or if available, may result in substantial dilution to our stockholders or otherwise impair the value of our common stock.

	●	A substantial number of the shares sold in this offering may be resold in the public market, which could cause the price of our common stock to decline.

	●	Our outstanding options, convertible preferred stock and convertible notes, along with the potential issuance of shares under our equity compensation plans and other arrangements, may have an adverse effect on the market price of our common stock.

	●	Our stock price may be volatile, and purchasers of our securities could incur substantial losses.

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THE OFFERING

The following summary contains basic terms about this offering and the common stock and is not intended to be complete. It may not contain all of the information that is important to you. You should read the more detailed information contained in this prospectus supplement, including but not limited to, the risk factors beginning on page S-6 of this prospectus supplement and the other risks described in our base prospectus and the annual and quarterly reports incorporated by reference therein.

Issuer		Lucid Diagnostics Inc.

Securities offered		18,000,000 shares of common stock

Public offering price		$1.00 per share

Common stock to be outstanding immediately after this offering		195,253,423 shares of common stock⁽¹⁾

Lock-ups		Our officers and directors will enter into lock-up agreements restricting the transfer of shares of or relating to our capital stock for 45 days after the closing of this offering. See “Underwriting” on page S-14 of this prospectus supplement.

Use of proceeds		We intend to use the net proceeds we receive from this offering for working capital and other general corporate purposes. See “Use of Proceeds” on page S-10 of this prospectus supplement.

Risk factors		See the section entitled “Risk Factors” beginning on page S-6 of this prospectus supplement and in the documents incorporated by reference herein for a discussion of factors you should consider carefully before deciding to invest in our common stock.

Market for securities		Our common stock is listed for trading on the Nasdaq Capital Market under the symbol “LUCD.”

(1)

Based on 177,253,423 shares of our common stock outstanding as of April 21, 2026 (inclusive of shares underlying unvested restricted stock awards). This amount does not include, as of April 21, 2026:

	●	12,299,585 shares of our common stock that were issuable upon exercise of our outstanding stock options, at a weighted average exercise price of $1.57 per share;

	●	13,294,267 shares of our common stock were issuable on March 13, 2026, upon conversion in full of, and in payment of final dividends on, the Series B Convertible Preferred Stock, or the “Series B Preferred Stock,” but are held in abeyance by us as a result of the beneficial limitations contained in the Series B Preferred Stock;

	●	an estimated 16,823,761 shares of our common stock that were issuable upon conversion of, and in payment of dividends on, our Series B-1 Convertible Preferred Stock, or the “Series B-1 Preferred Stock,” assuming that the Preferred Stock remains outstanding until May 6, 2026, its automatic conversion date, and all dividends on the Preferred Stock payable in shares of our common stock are paid in full (without taking into account the beneficial ownership limitation set forth therein); and

	●	an estimated 36,975,000 shares of our common stock that were issuable upon conversion of, and in payment of interest on, the 2024 Convertible Notes, assuming that the notes are converted in full on their maturity date and the maximum number of shares permitted under the notes to be issued in payment of interest are so issued (without taking into account the limitations on conversion set forth therein).

In addition, as of April 21, 2026, 929,500 shares of our common stock were reserved for issuance, but not subject to outstanding stock-based equity awards, under our Amended and Restated 2018 Long-Term Incentive Equity Plan, or the “2018 Plan,” and 1,662,087 shares of our common stock were reserved for issuance, but not yet issued, under our Employee Stock Purchase Plan, or the “ESPP.” The number of shares available under the 2018 Plan will automatically increase on January 1st of each year, through (and including) January 1, 2032, in an amount equal to 6% of the total number of shares of our common stock outstanding on December 31st of the preceding calendar year, unless our board of directors provides for a lesser amount. Similarly, the number of shares available for issuance under the ESPP will automatically increase on January 1st of each year, through (and including) January 1, 2032, in an amount equal to the lesser of (a) 2% of the total number of shares of our common stock outstanding on December 31st of the preceding calendar year, and (b) 1,000,000 shares, unless our board of directors provides for a lesser amount.

Furthermore, (i) we are party to a Sales Agreement with Maxim Group LLC, pursuant to which we may offer and sell up to $25 million in shares of our common stock in an “at the market offering” program; (ii) we are party to a management services agreement with PAVmed, pursuant to which PAVmed may elect to receive payment of the monthly fee under the management services agreement in cash or in shares of our common stock, with such shares valued at a price based on the current market price (under the terms of PAVmed’s convertible debt, it is required to elect that these payments be made in cash); and (iii) we are party to a payroll and benefits expense reimbursement agreement with PAVmed, pursuant to which PAVmed will pay certain payroll and benefit-related expenses on our behalf and we will reimburse PAVmed on a quarterly basis or at such other frequency as the parties may determine, in cash or, subject to approval by our board of directors and the board of directors of PAVmed, in shares of our common stock, or in a combination of cash and shares, with any such shares valued at a price based on the current market price.

S-5

RISK FACTORS

Any investment in our common stock involves a high degree of risk. Before you make a decision to invest in our common stock, you are urged to read and carefully consider the risks and uncertainties relating to an investment in our company set forth below, together with all of the other information contained or incorporated by reference in this prospectus supplement and the accompanying base prospectus. You should read and carefully consider the risks and uncertainties discussed under the item “Risk Factors” in our most recent annual report on Form 10-K and in any of our subsequent quarterly reports on Form 10-Q, as well as the other information in such reports and the risks, uncertainties and other information in the other documents we file with the SEC that are incorporated by reference in this prospectus supplement and the accompanying base prospectus, as such reports and documents may be amended, supplemented or superseded from time to time by documents we subsequently file with the SEC. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business and results of operations. If any of these risks actually occur, our business, financial condition or results of operations could be seriously harmed. In that event, the market price for our common stock could decline and you may lose all or part of your investment.

Risks Related to this Offering

You will experience immediate and substantial dilution in the net tangible book value per share of the common stock you purchase.

The price per share of our common stock offered hereby is substantially higher than the pro forma net tangible book value per share of our common stock. As a result, investors purchasing shares of our common stock in this offering will incur immediate dilution of approximately $0.86 per share, after giving effect to the sale of all shares of our common stock offered hereby at a public offering price of $1.00 per share, and after deducting underwriting discounts and commissions and estimated offering expenses payable by us. See “Dilution” on page S-12 of this prospectus supplement for a more detailed discussion of the dilution you will incur if you purchase shares in this offering.

This offering could cause the price of our common stock to decline.

The shares of common stock offered hereby are being sold at a price of $1.00 per share and represent approximately 10.2% of our outstanding common stock as of April 22, 2026. As a result, the resale of the shares offered hereby in the public market, or the perception that such sales may occur, could immediately adversely affect the price of our common stock on the Nasdaq Capital Market. We cannot predict the effect, if any, that market sales of those shares of common stock or the availability of those shares of common stock for sale will have on the market price of our common stock.

Our management will have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

Our management will have broad discretion in the application of the net proceeds from this offering, and our stockholders will not have the opportunity as part of their investment decision to assess whether the net proceeds are being used appropriately. Because of the number and variability of factors that will determine our use of the net proceeds from this offering, their ultimate use may vary substantially from their currently intended use. The failure by our management to apply these funds effectively could harm our business. See “Use of Proceeds” on page S-10 of this prospectus supplement for a description of our proposed use of proceeds from this offering.

S-6

Risks Related to Ownership of Our Common Stock

Even after giving effect to this offering, we expect to require additional capital funding, which may not be available on acceptable terms, or at all, or if available, may result in substantial dilution to our stockholders or otherwise impair the value of our common stock.

Even after giving effect to this offering, as we have not generated significant revenue or cash flow to date, we expect to require additional capital funding in order to make investments to support our business growth. We may seek to raise required additional capital through public or private equity or debt offerings, through loans, through arrangements with strategic partners or through other sources. Such capital may not be available on acceptable terms, or at all. If we do not have, or are not able to obtain, sufficient funds, we may have to delay product development initiatives or reduce our research and development, clinical trial, marketing, customer support or other commercial activities.

To the extent we are successful in raising additional capital by issuing equity securities, our stockholders may experience substantial dilution and the new equity securities may have greater rights, preferences or privileges than our existing common stock. Any additional shares of our common stock or other securities convertible into or exchangeable for our common stock may be sold at prices lower (or higher) than the price paid by purchasers in this offering. Furthermore, sales of a substantial number of shares of our common stock in the public markets, or the perception that such sales could occur, could depress the market price of our common stock. In the case of certain issuances of equity securities, if the effective sales price per share is less than the then-current conversion price under the 2024 Convertible Notes, the conversion price of the 2024 Convertible Notes will be reduced to such lower sales price, which would increase the number of shares of our common stock upon conversion of such notes, thereby further diluting our stockholders if the notes are converted in accordance with their terms.

To the extent we are successful in raising additional capital by issuing debt securities or incurring loans, the holders of such securities or loans will have priority in payment over the holders of our equity securities. In addition, the terms of those debt securities or loan arrangements may include negative covenants or other restrictions on our business that could impair our operational flexibility, including restricting our ability to pursue our business strategy, and could also require us to incur substantial interest expense.

A substantial number of the shares sold in this offering may be resold in the public market, which could cause the price of our common stock to decline.

The sale of shares to be issued in this offering in the public market, or any future sales of a substantial number of shares of our common stock in the public market, or the perception that such sales may occur, could adversely affect the price of our common stock on the Nasdaq Capital Market. We cannot predict the effect, if any, that market sales of those shares of common stock or the availability of those shares of common stock for sale will have on the market price of our common stock.

Our outstanding options, convertible preferred stock and convertible notes, along with the potential issuance of shares under our equity compensation plans and other arrangements, may have an adverse effect on the market price of our common stock.

As of April 21, 2026, in addition to our outstanding shares of common stock:

	●	12,299,585 shares of our common stock were issuable upon exercise of our outstanding stock options, at a weighted average exercise price of $1.57 per share;

	●	13,294,267 shares of our common stock were issuable on March 13, 2026, upon conversion in full of, and in payment of final dividends on, the Series B Convertible Preferred Stock, or the “Series B Preferred Stock,” but are held in abeyance by us as a result of the beneficial limitations contained in the Series B Preferred Stock;

	●	an estimated 16,823,761 shares of our common stock were issuable upon conversion of, and in payment of dividends on, the Series B-1 Preferred Stock, assuming that the Preferred Stock remains outstanding until its automatic conversion date on May 6, 2026, and all dividends on the Preferred Stock payable in shares of our common stock are paid in full (without taking into account the beneficial ownership limitation set forth therein); and

	●	an estimated 36,975,000 shares of our common stock were issuable upon conversion of, and in payment of interest on, the 2024 Convertible Notes, assuming that the notes are converted in full on their maturity date and the maximum number of shares permitted under the notes to be issued in payment of interest are so issued (without taking into account the limitations on conversion set forth therein).

S-7

In addition, as of April 21, 2026, 929,500 shares of our common stock were reserved for issuance, but not subject to outstanding stock-based equity awards, under the 2018 Plan, and 1,662,087 shares of our common stock were reserved for issuance, but not yet issued, under the ESPP. The number of shares available under the 2018 Plan will automatically increase on January 1st of each year, through (and including) January 1, 2032, in an amount equal to 6% of the total number of shares of our common stock outstanding on December 31st of the preceding calendar year, unless our board of directors provides for a lesser amount. Similarly, the number of shares available for issuance under the ESPP will automatically increase on January 1st of each year, through (and including) January 1, 2032, in an amount equal to the lesser of (a) 2% of the total number of shares of our common stock outstanding on December 31st of the preceding calendar year, and (b) 1,000,000 shares, unless our board of directors provides for a lesser amount.

Any issuance of these shares will dilute our other equity holders, which could cause the price of our common stock to decline. In addition, the sale of these shares in the public market, or the perception that such sales may occur, could adversely affect the price of our common stock.

Our stock price may be volatile, and purchasers of our securities could incur substantial losses.

Our stock price is likely to be volatile. The stock market in general, and the market for life science companies, and medical device companies in particular, have experienced extreme volatility that has often been unrelated to the operating performance of particular companies. As a result of this volatility, investors may experience losses on their investment in our common stock.

For example, on April 22, 2026, the last reported sale price of our common stock was $1.31. In the last six months, between October 23, 2025 and April 22, 2026, the intra-day sales price of our common stock fluctuated between a reported low sale price of $0.9923 and a reported high sales price of $1.6293. We may incur rapid and substantial increases or decreases in our stock price in the foreseeable future that do not coincide in timing with the disclosure of news or developments by us.

The market price for our common stock may be influenced by many factors, including the following:

	●	factors in the public trading market for our stock that may produce price movements that may or may not comport with macro, industry or company-specific fundamentals, including, without limitation, the sentiment of retail investors (including as may be expressed on financial trading and other social media sites and online forums), the direct access by retail investors to broadly available trading platforms, the amount and status of short interest in our securities, access to margin debt, trading in options and other derivatives on our common stock and any related hedging and other trading factors;

	●	speculation in the press or investment community about our company or industry;

	●	our ability to successfully commercialize, and realize revenues from sales of, any products we may develop;

	●	the performance, safety and side effects of any products we may develop;

	●	the success of competitive products or technologies;

	●	results of clinical studies of any products we may develop or those of our competitors;

	●	regulatory or legal developments in the U.S. and other countries, especially changes in laws or regulations applicable to any products we may develop;

S-8

	●	introductions and announcements of new products by us, our commercialization partners, or our competitors, and the timing of these introductions or announcements;

	●	actions taken by regulatory agencies with respect to our products, clinical studies, manufacturing process or sales and marketing terms;

	●	variations in our financial results or those of companies that are perceived to be similar to us;

	●	the success of our efforts to acquire or in-license additional products or other products we may develop;

	●	developments concerning our collaborations, including but not limited to those with our sources of manufacturing supply and our commercialization partners;

	●	developments concerning our ability to bring our manufacturing processes to scale in a cost-effective manner;

	●	announcements by us or our competitors of significant acquisitions, strategic partnerships, joint ventures or capital commitments;

	●	developments or disputes concerning patents or other proprietary rights, including patents, litigation matters and our ability to obtain patent protection for our products;

	●	our ability or inability to raise additional capital and the terms on which we raise it;

	●	the recruitment or departure of key personnel;

	●	changes in the structure of healthcare payment systems;

	●	market conditions in the medical device, pharmaceutical and biotechnology sectors;

	●	actual or anticipated changes in earnings estimates or changes in stock market analyst recommendations regarding our common stock, other comparable companies or our industry generally;

	●	trading volume of our common stock;

	●	sales of our common stock by us or our stockholders;

	●	general economic, industry and market conditions; and

	●	the other risks described and incorporated by reference in this “Risk Factors” section.

These broad market and industry factors may seriously harm the market price of our common stock, regardless of our operating performance. In the past, following periods of volatility in the market, securities class action litigation has often been instituted against companies. Such litigation, if instituted against us, could result in substantial costs and diversion of management’s attention and resources, which could materially and adversely affect our business, financial condition, results of operations and growth prospects.

We do not expect to pay any dividends in the foreseeable future.

We have not paid any cash dividends on our shares of common stock to date. The payment of cash dividends on our common stock in the future will be dependent upon our revenues and earnings, if any, capital requirements and general financial condition and will be within the discretion of our board of directors. It is the present intention of our board of directors to retain all earnings, if any, for use in our business operations and, accordingly, our board of directors does not anticipate declaring any dividends on our common stock in the foreseeable future. As a result, any gain you will realize on our common stock will result solely from the appreciation of such shares.

S-9

USE OF PROCEEDS

We estimate the net proceeds to us from this offering will be approximately $16.8 million, after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

We intend to use the net proceeds from the sale of our common stock in this offering for working capital and general corporate purposes. We have not identified the amounts we will spend on any specific purpose. The amounts actually expended for any purpose may vary significantly depending upon numerous factors, including assessments of potential market opportunities, the results of clinical trials and regulatory developments. In the event any net proceeds are not immediately applied, we may temporarily deposit them in our bank accounts as cash and cash equivalents or purchase short-term investments.

S-10

CAPITALIZATION

The following table sets forth our cash position and capitalization as of April 21, 2026, as follows:

	●	on an unaudited historical actual basis;

	●	on an unaudited pro forma basis after giving effect to the conversion in full of, and the payment of final dividends on, the Series B Preferred Stock on March 13, 2026; and

	●	on an unaudited pro forma as adjusted basis, after giving further effect to the sale by us of the shares of our common stock offered hereby at an offering price of $1.00 per share, and after deducting underwriting discounts and commissions and estimated offering expenses payable by us.

You should read this table together with our consolidated financial statements and notes thereto, as well as “Management’s Discussion and Analysis of Financial Condition and Results of Operations” and the other financial information included therein, incorporated by reference in this prospectus supplement from our SEC filings, including our annual report on Form 10-K for the fiscal year ended December 31, 2025.

	Historical						Pro Forma
In Thousands of Dollars	Actual			Pro Forma			As Adjusted
	(unaudited)			(unaudited)			(unaudited)
Assets:
Cash	$	34,705		$	34,705		$	51,505
Total assets	$	40,445		$	40,445		$	57,245

Liabilities:
Senior Secured Convertible Notes - at fair value	$	24,000		$	24,000		$	24,000
Total liabilities	$	29,509		$	29,509		$	29,509

Stockholders’ Equity (Deficit):
Preferred stock, $0.001 par value, 20,000,000 shares authorized; Series B and Series B-1 Convertible Preferred Stock, 54,419 shares issued and outstanding at December 31, 2025	$	54,274		$	10,134		$	10,134
Common stock, $0.001 par value, 300,000,000 shares authorized as of December 31, 2025; 131,098,762 shares issued and outstanding as of December 31, 2025		131			174			192
Additional paid-in capital		230,866			284,682			301,464
Accumulated deficit		(274,335	)		(284,054	)		(284,054	)
Total stockholders’ equity (deficit)	$	10,936		$	10,936		$	27,736

Total liabilities and stockholders’ equity (deficit)	$	40,445		$	40,445		$	57,245

The foregoing information does not take into account the exercise of our outstanding options, the conversion of our outstanding convertible preferred stock or convertible notes, or the issuance of shares under our equity plans or other arrangements, as set forth in footnote 1 in “Prospectus Summary – The Offering.”

S-11

DILUTION

If you invest in our shares, your ownership interest will be diluted to the extent of the difference between the price you paid per share of common stock in this offering and the net tangible book value per share of our common stock after this offering. Net tangible book value per share represents total tangible assets less total liabilities, divided by the number of shares of our common stock outstanding.

Our net tangible book value as of December 31, 2025 was approximately $10.6 million, or approximately $0.08 per share of our common stock issued and outstanding, on an unaudited historical basis as of such date.

Our net tangible book value as of December 31, 2025 would have been approximately $10.6 million, or approximately $0.06 per share of our common stock issued and outstanding, on an unaudited pro forma basis as of such date, after giving effect to the conversion in full of, and the payment of final dividends on, the Series B Preferred Stock.

Our net tangible book value as of December 31, 2025 would have been approximately $27.4 million, or approximately $0.14 per share of our common stock issued and outstanding, on an unaudited pro forma as adjusted basis as of such date, after giving further effect to the sale by us of 18,000,000 shares of our common stock in this offering at an offering price of $1.00 per share, for aggregate gross proceeds of approximately $18.0 million, and the payment of $1.2 million in underwriting discounts and commissions and estimated offering expenses payable by us. This represents an immediate increase in net tangible book value of $0.08 per share of our common stock to existing stockholders and an immediate dilution of $0.86 per share of our common stock to new investors purchasing shares of our common stock in this offering.

The following table illustrates the dilution on a per share of common stock basis for investors purchasing shares of our common stock in this offering:

Public offering price per share in this offering			$	1.00
Pro forma net tangible book value per share as of December 31, 2025	$	0.06
Increase in net tangible book value per share attributable to this offering	$	0.08
Pro forma as adjusted net tangible book value per share as of December 31, 2025			$	0.14
Dilution per share to new investors in this offering			$	0.86

The per share calculations above are based on the number of shares of our common stock issued and outstanding as of December 31, 2025, as follows: 131,098,762 shares on an audited historical basis, 173,663,711 on an unaudited pro forma basis and 191,663,711 shares on an unaudited pro forma as adjusted basis (in each case, excluding 6,584,240 shares of unvested restricted stock awards granted under our incentive equity plan).

To the extent that other shares are issued, investors purchasing shares in this offering could experience more or less dilution. In addition, we may choose to raise additional capital due to market conditions or strategic considerations, even if we believe we have sufficient funds for our current or future operating plans. To the extent that additional capital is raised through the sale of equity or convertible debt securities, the issuance of those securities could result in more or less dilution to investors in this offering.

S-12

DESCRIPTION OF COMMON STOCK

Upon consummation of the offering, 195,253,423 shares of our common stock will be outstanding. This amount does not include the shares of our common stock issuable upon the exercise of our outstanding options or the conversion of our outstanding convertible preferred stock and convertible notes, or the issuance of shares under our equity plans or other arrangements, as set forth in footnote 1 in “Prospectus Summary – The Offering.” For a description of our common stock, please see “Description of Capital Stock” in the accompanying base prospectus.

S-13

UNDERWRITING

We are offering the shares of common stock described in this prospectus supplement and the accompanying base prospectus through the underwriters listed below. Canaccord Genuity LLC, or “Canaccord Genuity,” and BTIG, LLC, or “BTIG,” are acting as the book-running managers of this offering. The underwriters named below have agreed to buy, subject to the terms of the underwriting agreement, the number of securities listed opposite its name below. The underwriters are committed to purchase and pay for all of the securities if any are purchased.

Underwriter	Number of Shares of Common Stock
Canaccord Genuity LLC		9,000,000
BTIG, LLC		9,000,000
Total		18,000,000

The underwriters have advised us that they propose to offer the shares of common stock to the public at a price of $1.00 per share. The underwriters propose to offer the shares of common stock to certain dealers at the same price less a concession of not more than $0.036 per share. After the offering, these figures may be changed by the underwriters.

Underwriting Discounts and Expenses

The following table summarizes the underwriting discounts and commissions to be paid to the underwriters by us.

	Per Share (1)		Total
Public offering price	$	1.00	$	18,000,000
Underwriting discount to be paid to the underwriters by us	$	0.06	$	1,080,000
Proceeds to us (before expenses)	$	0.94	$	16,920,000

(1)

In addition to the underwriting discount, we have also agreed to reimburse the underwriters for certain out-of-pocket accountable expenses incurred by them in connection with this offering, up to a maximum of $75,000, including, but not limited to, the underwriters’ legal fees, all travel and reasonable out of pocket expenses incurred in connection with this offering.

We estimate that the total expenses of this offering, excluding underwriting discounts and commissions, will be $120,000. These expenses are payable by us.

S-14

Indemnification

We have agreed to indemnify the underwriters against certain liabilities, including liabilities under the Securities Act, or to contribute to payments that the underwriters may be required to make in respect of those liabilities.

Lock-up Agreements

We have agreed, subject to limited exceptions, for a period of 45 days after the closing of this offering, and our officers and directors have agreed, subject to limited exceptions, for a period of 45 days after the closing of this offering, not to offer, sell, contract to sell, pledge, grant any option to purchase, make any short sale or otherwise dispose of, directly or indirectly any shares of common stock or any securities convertible into or exchangeable for our common stock either owned as of the date of the underwriting agreement or thereafter acquired without the prior written consent of Canaccord Genuity. Canaccord Genuity may, in its sole discretion and at any time or from time to time before the termination of the lock-up period, without notice, release all or any portion of the securities subject to lock-up agreements.

Price Stabilization, Short Positions and Penalty Bids

In connection with this offering, the underwriters may engage in activities that stabilize, maintain or otherwise affect the price of our securities during and after this offering, including: stabilizing transactions; short sales; purchases to cover positions created by short sales; imposition of penalty bids; and syndicate covering transactions.

Stabilizing transactions consist of bids or purchases made for the purpose of preventing or retarding a decline in the market price of our shares of common stock while this offering is in progress. Stabilization transactions permit bids to purchase the underlying security so long as the stabilizing bids do not exceed a specified maximum.

The underwriters also may impose a penalty bid. This occurs when a particular underwriter repays to the underwriters a portion of the underwriting discount received by it because an underwriter has repurchased shares sold by or for the account of that underwriter in stabilizing transactions.

These stabilizing transactions, the imposition of penalty bids and syndicate covering transactions may have the effect of raising or maintaining the market price of our common stock or preventing or retarding a decline in the market price of our common stock. As a result of these activities, the price of our common stock may be higher than the price that otherwise might exist in the open market. The underwriters may carry out these transactions on Nasdaq, in the over-the-counter market or otherwise. Neither we nor the underwriters make any representation or prediction as to the effect that the transactions described above may have on the price of the shares. Neither we, nor any of the underwriters make any representation that the underwriters will engage in these stabilization transactions or that any transaction, once commenced, will not be discontinued without notice.

Electronic Distribution

This prospectus supplement in electronic format may be made available on websites or through other online services maintained by the underwriters, or by their affiliates. Other than this prospectus supplement in electronic format, the information on the underwriters’ websites and any information contained in any other websites maintained by the underwriters is not part of this prospectus supplement or the registration statement of which this prospectus supplement forms a part, has not been approved and/or endorsed by us or the underwriters in their capacity as underwriters, and should not be relied upon by investors.

Other

From time to time, the underwriters may in the future provide, various investment banking and other financial services for us and, may in the future receive, customary fees. Except for the services provided in connection with this offering, the underwriters have not provided any investment banking or other financial services during the 180-day period preceding the date of this prospectus supplement.

Trading Market

Our common stock is traded on the Nasdaq Capital Market under the symbol “LUCD.”

Transfer Agent

The transfer agent for our common stock to be issued in this offering is Continental Stock Transfer & Trust Company, located at One State Street Plaza, 30th Floor, New York, New York 10004.

S-15

LEGAL MATTERS

The validity of the securities offered will be passed upon for us by Graubard Miller, New York, New York. Duane Morris LLP, New York, New York, is acting as counsel for the underwriters in connection with this offering.

EXPERTS

The consolidated financial statements of Lucid Diagnostics Inc. and Subsidiaries as of December 31, 2025 and for the year then ended, which are incorporated in this prospectus supplement by reference to the Annual Report on Form 10-K for the year ended December 31, 2025, have been so incorporated in reliance on the report of CBIZ CPAs P.C., an independent registered public accounting firm (which report includes an explanatory paragraph as to the Company’s ability to continue as a going concern), given on the authority of said firm as experts in auditing and accounting.

The consolidated financial statements of Lucid Diagnostics Inc. and Subsidiaries as of December 31, 2024 and for the year then ended, which are incorporated in this prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2025, have been so incorporated in reliance on the report of Marcum LLP, an independent registered public accounting firm (which report includes an explanatory paragraph as to the Company’s ability to continue as a going concern), given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

We file annual, quarterly and current reports, proxy statements and other information with the Securities and Exchange Commission. Our SEC filings are available to the public over the Internet at the SEC’s web site at http://www.sec.gov. You may also read and copy any document we file with the SEC at the SEC’s public reference room at 450 Fifth Street, N.W., Washington, D.C. 20549. Please call the SEC at 1-800-SEC-0330 for further information about the public reference room.

We have filed with the SEC a registration statement under the Securities Act relating to the offering of these securities. The registration statement, including the attached exhibits, contains additional relevant information about us and the securities. This prospectus supplement and the accompanying base prospectus do not contain all of the information set forth in the registration statement. You can obtain a copy of the registration statement, at prescribed rates, from the SEC at the address listed above.

Statements contained in this prospectus supplement and the accompanying base prospectus regarding the contents of any contract or other document that is filed as an exhibit to the registration statement or any SEC filing incorporated by reference in the registration statement are not necessarily complete, and each such statement is qualified in all respects by reference to the full text of such contract or other document filed as an exhibit to the registration statement or any SEC filing incorporated by reference in the registration statement.

The registration statement and our SEC filings, including the documents referred to below under “Information Incorporated by Reference,” are also available on our website, www.luciddx.com. We have not incorporated by reference into this prospectus supplement the information on our website, and you should not consider it to be a part of this prospectus supplement.

S-16

INFORMATION INCORPORATED BY REFERENCE

This prospectus supplement incorporates by reference the documents listed below, and all filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after the date hereof and prior to the sale of all of the securities offered hereby:

	●	the Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (filed on March 25, 2026);

	●	the Current Report on Form 8-K dated April 23, 2026 (filed on April 23, 2026); and

	●	the Form 8-A filed on October 12, 2021 registering our common stock under Section 12(b) of the Exchange Act, as updated by Exhibit 4.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (filed on March 25, 2026).

Notwithstanding the foregoing, we are not incorporating any document or portion thereof or information deemed to have been furnished and not filed in accordance with SEC rule.

Any statement contained in a document filed before the date of this prospectus supplement and incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained herein modifies or supersedes such statement. Any information that we file after the date of this prospectus supplement with the SEC and incorporated by reference herein will automatically modify and supersede the information contained in this prospectus supplement and in any document previously incorporated by reference in this prospectus supplement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement.

We will provide you with a copy of the documents incorporated by reference in this prospectus supplement, without charge, upon written or oral request directed to Lucid Diagnostics Inc., 360 Madison Avenue, 25^th Floor, New York, New York 10017, telephone number (917) 813-1828. You may also access the documents incorporated by reference as described under “Where You Can Find More Information.”

S-17

PROSPECTUS

Lucid Diagnostics Inc.

$175,000,000

Common Stock, Preferred Stock, Debt Securities, Warrants and Units

We may offer and sell from time to time shares of common stock, shares of preferred stock, debt securities, warrants and/or units comprised of one or more of the other classes of securities offered hereby, at an aggregate initial offering price not to exceed $175,000,000. The securities may be offered separately, together, or in series, and in amounts, at prices and on other terms to be determined at the time of each offering. We will specify the terms of the securities being offered in one or more prospectus supplements, which may also supplement, update or amend information contained or incorporated by reference in this prospectus.

We may sell the securities directly to investors, to or through underwriters or dealers or through agents designated from time to time, among other methods. The prospectus supplement for each offering will describe in detail the specific plan of distribution for the securities. The prospectus supplement also will set forth the price to the public of such securities, any placement agent’s fees or underwriter’s discounts and commissions, and the net proceeds we expect to receive from the sale of the securities.

Our common stock is listed for trading on the Capital Market of The Nasdaq Stock Market LLC, or “Nasdaq,” under the symbol “LUCD.” On March 24, 2026, the last reported sale price of our common stock was $1.20. As of the date of this prospectus, none of the other securities that we may offer by this prospectus are listed on any national securities exchange or automated quotation system.

We are an “emerging growth company” as defined in the Jumpstart Our Business Startups Act of 2012 and have elected to comply with certain reduced public company reporting requirements.

Investing in our securities involves a high degree of risk. See “Risk Factors” in this prospectus on page 5 and in any supplements for a discussion of information that should be considered in connection with an investment in our securities.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus. Any representation to the contrary is a criminal offense.

The date of this prospectus is March 26, 2026

TABLE OF CONTENTS

PROSPECTUS

ABOUT THIS PROSPECTUS	ii
MARKET AND INDUSTRY DATA	ii
TRADEMARKS	iii
NOTE ON FORWARD-LOOKING STATEMENTS AND RISK FACTOR SUMMARY	iii
GLOSSARY	iv
PROSPECTUS SUMMARY	1
RISK FACTORS	5
USE OF PROCEEDS	5
DESCRIPTION OF CAPITAL STOCK	6
DESCRIPTION OF DEBT SECURITIES	11
DESCRIPTION OF WARRANTS	17
DESCRIPTION OF THE UNITS	18
PLAN OF DISTRIBUTION OF SECURITIES	19
LEGAL MATTERS	22
EXPERTS	22
WHERE YOU CAN FIND MORE INFORMATION	22
INFORMATION INCORPORATED BY REFERENCE	23

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement under the Securities Act of 1933, as amended, or the “Securities Act,” on Form S-3 that we filed with the Securities and Exchange Commission, or the “SEC,” using a “shelf” registration process. Under this shelf process, we may, from time to time, sell or issue any of the combination of securities described in this prospectus in one or more offerings with a maximum aggregate offering price of up to $175,000,000.

This prospectus provides you with a general description of the securities we may offer under the registration statement. Each time we sell securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement may also add, update or change information contained in this prospectus. If there is any inconsistency between the information in this prospectus and any prospectus supplement, you should rely on the information in that prospectus supplement. You should read both this prospectus and any prospectus supplement, together with the additional information described below under the heading “Where You Can Find More Information” and “Information Incorporated by Reference.”

You should rely only on the information contained or incorporated by reference in this prospectus and any prospectus supplement or issuer free writing prospectus relating to a particular offering. We have not authorized anyone to provide you with different information and, if provided, such information or representations must not be relied upon as having been authorized by us. Neither this prospectus nor any prospectus supplement nor any issuer free writing prospectus shall constitute an offer to sell or a solicitation of an offer to buy offered securities in any jurisdiction in which it is unlawful for such person to make such an offering or solicitation. This prospectus does not contain, and any prospectus supplement or issuer free writing prospectus will not contain, all of the information included in the registration statement. For a more complete understanding of the offering of the securities, you should refer to the registration statement, including its exhibits.

You should not assume that the information appearing in this prospectus is accurate as of any date other than the date on the front cover of this prospectus. You should not assume that the information contained in any prospectus supplement or in the documents incorporated by reference herein or therein or in any issuer free writing prospectus is accurate as of any date other than the respective dates of those documents. Our business, financial condition, results of operations, and prospects may have changed since that date.

Unless otherwise indicated or unless the context otherwise requires, all references in this prospectus to “Lucid Diagnostics,” the “Company,” and “we,” “us” and “our” refer to Lucid Diagnostics Inc., a Delaware corporation, and its subsidiaries.

MARKET AND INDUSTRY DATA

We obtained the market, industry and competitive position data used throughout this prospectus and the documents incorporated by reference in this prospectus from our own internal estimates and research, as well as from independent market research, industry and general publications and surveys, governmental agencies and publicly available information in addition to research, surveys and studies conducted by third parties. Internal estimates are derived from publicly available information released by industry analysts and third-party sources, our internal research and our industry experience, and are based on assumptions made by us based on such data and our knowledge of our industry and market, which we believe to be reasonable. In some cases, we do not expressly refer to the sources from which this data is derived. In that regard, when we refer to one or more sources of this type of data in any paragraph, you should assume that other data of this type appearing in the same paragraph is derived from the same sources, unless otherwise expressly stated or the context otherwise requires. In addition, while we believe the industry, market and competitive position data included or incorporated by reference in this prospectus are reliable and based on reasonable assumptions, such data involve risks and uncertainties and are subject to change based on various factors, including those discussed in the section titled “Risk Factors.” These and other factors could cause results to differ materially from those expressed in the estimates made by the independent parties or by us.

TRADEMARKS

NOTE ON FORWARD-LOOKING STATEMENTS AND RISK FACTOR SUMMARY

	●	our limited operating history;

	●	our financial performance, including our ability to generate revenue;

	●	our ability to obtain regulatory approval for the commercialization of our products;

	●	the risk that the FDA will cease to exercise enforcement discretion with respect to LDTs, like EsoGuard;

	●	our ability of our products to achieve market acceptance;

	●	our success in retaining or recruiting, or changes required in, our officers, key employees or directors;

	●	our potential ability to obtain additional financing when and if needed;

	●	our ability to protect our intellectual property;

	●	our ability to complete strategic acquisitions;

	●	our ability to manage growth and integrate acquired operations;

	●	the potential liquidity and trading of our securities;

	●	our regulatory and operational risks;

	●	cybersecurity risks;

	●	risks related to the health-related emergencies;

	●	risks related to our relationship with PAVmed; and

	●	our estimates regarding expenses, future revenue, capital requirements and needs for additional financing.

Should one or more of these risks or uncertainties materialize, or should any of our expectations, believes or assumptions otherwise prove incorrect, actual results, developments and their effects on us may vary in material respects from those projected in these forward-looking statements. Accordingly, you should not rely on these forward-looking statements. We do not undertake any obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required under applicable securities laws.

iii

GLOSSARY

Unless otherwise stated in this prospectus:

	●	“510(k)” refers to a premarket notification, submitted to the FDA by a manufacturer pursuant to section 510(k) of the FDCA and 21 CFR § 807 subpart E, of its intent to market a non-exempt Class I or Class II medical device intended for human use, for which a PMA application is not required, to demonstrate that the device to be marketed is as safe and effective, that is, substantially equivalent to, a legally marketed device, commonly known as a “predicate”; and “510(k) clearance” refers to a determination by FDA under 21 CFR § 807.100 that a medical device has been found to be substantially equivalent to a legally marketed predicate device and can be marketed in the U.S.

	●	“BE” refers to Barrett’s Esophagus, an esophageal precancer and complication of GERD in which surface cells lining the lower esophagus undergo precancerous metaplastic or dysplastic transformation from repeated exposure to stomach fluid, including acid, refluxing into the lower esophagus. BE can be nondysplastic or dysplastic. In nondysplastic BE, or “NDBE,” there is no dysplasia. In dysplastic BE, there is dysplasia, which can be early, low-grade dysplasia, or “LGD,” or advanced, high-grade dysplasia, or “HGD.”

	●	“CE Mark” refers to “Conformité Européenne” Mark, a mark indicating that a product such as a medical device conforms to the essential requirements of the relevant European directive and may be marketed in European Economic Area (the European Union, Norway, Iceland, and Lichtenstein), Switzerland, and, until July 1, 2023, the United Kingdom; for medical devices and in vitro devices the relevant directives had been Medical Device Directive 93/42/EEC and In-Vitro Diagnostic Medical Devices Directive 98/79/EC, respectively, but have been or will soon be replaced by Regulation (EU) 2017/745 and Regulation (EU) 2017/746, respectively.

	●	“CLIA” refers to the Clinical Laboratory Improvement Amendments of 1988 and associated regulations set forth in 42 CFR § 493, through which CMS regulates all non-research laboratory testing performed on humans in the U.S., including LDTs.

	●	“CMS” refers to the U.S. Center for Medicare and Medicaid Services.

	●	“EAC” refers to esophageal adenocarcinoma, the most common and highly lethal form of esophageal cancer which universally arises from BE.

	●	“EGD” refers to esophagogastroduodenoscopy, or upper gastrointestinal endoscopy, an invasive diagnostic or therapeutic procedure typically performed in an ambulatory endoscopy or surgery center under intravenous anesthesia, which allows the operator to visualize, sample and in some circumstances treat conditions of the esophagus, stomach, or duodenum.

	●	“FDA” refers to the U.S. Food and Drug Administration.

	●	“FDCA” refers to the U.S. Food, Drug, and Cosmetic Act as codified in 21 CFR.

	●	“GERD” refers to gastroesophageal reflux disease, commonly known as chronic heart burn, acid reflux, or just reflux, a symptomatic or asymptomatic pathologic condition where dysfunction of the muscular valve between the stomach and esophagus allows stomach fluid, including acid, to inappropriately reflux into the lower esophagus.

	●	“IVD” refers to an in vitro diagnostic product, defined by FDA as a reagent, instrument, or system intended for use in diagnosis of disease or other conditions; such a product is intended for use in the collection, preparation, and examination of specimens take from the human body and is a device as defined in the FDCA.

	●	“LDT” or “laboratory developed test” refers to a diagnostic test, defined by FDA as “an IVD that is intended for clinical use and designed, manufactured and used within a single laboratory,” which is generally subject only to self-certification of analytical validity under the CMS CLIA program.

	●	“PAVmed” refers to PAVmed Inc., our parent company.

	●	“PMA” refers to premarket approval, the most stringent FDA premarket medical device scientific and regulatory review process, codified in 21 CFR § 814, which, due to the risk associated with Class III devices, requires sufficient valid scientific evidence in addition to general and special controls to assure that it is safe and effective for its intended use(s).

PROSPECTUS SUMMARY

This summary contains basic information about us and our business but does not contain all of the information that is important to your investment decision. You should read this summary together with the more detailed information contained elsewhere in this prospectus and the documents incorporated herein by reference before making an investment decision. Investors should carefully consider the information set forth under the caption “Risk Factors” appearing elsewhere in this prospectus, including those incorporated by reference herein.

Our Company

Recent Developments

Medicare Coverage

Department of Veteran Affairs

Real-World Experience Data

Board Appointment

Clinical Study Publications

Corporate Information

We are a Delaware corporation formed on May 8, 2018 and are a majority owned subsidiary of PAVmed. Our executive offices are located at 360 Madison Avenue, 25^th Floor, New York, NY 10017, and our telephone number is (917) 813-1828. Our corporate website is www.luciddx.com. The information contained on or that can be accessed through our website is not incorporated by reference into this prospectus and you should not consider information on our website to be part of this prospectus or in deciding whether to purchase our securities.

Implications of Being an Emerging Growth Company

Risk Factor Summary

Risks Associated with Our Financial Condition

	●	We have incurred operating losses since our inception and may not be able to achieve profitability.

	●	We have concluded there is substantial doubt of our ability to continue as a going concern and our independent registered public accounting firm’s report on our financial statements contains an explanatory paragraph describing our ability to continue as a going concern.

	●	To raise capital, we have issued a significant amount of convertible securities under which we expect to issue a correspondingly significant amount of shares of our common stock upon conversion thereof. In addition, we may issue shares of our capital stock or debt securities in the future in order to raise capital to fund our operations. All of the foregoing would dilute the equity interest of our stockholders and might cause a change in control of our ownership.

	●	We expect to need additional capital funding, which may be compounded by our obligations to our parent company, PAVmed, which requires its own additional capital funding.

	●	Our quarterly operating results could be subject to significant fluctuation, which could increase the volatility of our stock price and cause losses to our stockholders.

	●	Servicing our indebtedness may require a significant amount of cash, and the restrictive covenants contained in our indebtedness could adversely affect our business plan, liquidity, financial condition, and results of operations.

Risks Associated with Our Business

	●	Since we have a limited operating history, and have not generated any significant revenues to date, you will have little basis upon which to evaluate our ability to achieve our business objective.

	●	The markets in which we operate are attractive and other companies or institutions may develop and market novel or improved technologies, which may make the EsoGuard or EsoCheck technologies less competitive or obsolete.

	●	We expect to derive substantially all of our revenues from the EsoGuard and EsoCheck products.

	●	We are highly dependent on our license agreement with CWRU, the termination of which would prevent us from commercializing our products, and which imposes significant obligations on us.

	●	Our products may never achieve market acceptance.

	●	Recommendations in published clinical practice guidelines issued by various organizations, including professional societies and federal agencies may significantly affect payors’ willingness to cover, and physicians’ willingness to prescribe, our products and services.

Risks Associated with Healthcare Regulation, Billing and Reimbursement, and Product Safety and Effectiveness

	●	If private or governmental third-party payors do not maintain reimbursement for our products at adequate reimbursement rates, we may be unable to successfully commercialize our products which would limit or slow our revenue generation and likely have a material adverse effect on our business.

	●	If our clinical studies do not satisfy providers, payors, patients and others as to the reliability and performance of our EsoGuard test and the EsoCheck device, or any other product or service we may develop and seek to commercialize, we may experience reluctance or refusal on the part of physicians to order, and third-party payors to pay for, such test.

	●	Clinical laboratories and medical diagnostic companies are subject to extensive and frequently changing federal, state, and local laws. We could be subject to significant fines and penalties if we fail (or if our prior unrelated third-party laboratory partner previously failed) to comply with these laws and regulations.

	●	Many aspects of our business, beyond the specific elements described above, are subject to complex, intertwined, costly and/or burdensome federal health care laws and regulations which may open to interpretation and be subject to varying levels of discretionary enforcement. If we fail to comply with these laws and regulations, we could face substantial penalties and our business, operations and financial condition could be adversely affected.

	●	Due to billing complexities in the diagnostic and laboratory service industry, we may not be able to collect payment for the EsoGuard tests we perform.

	●	The results of our clinical trials may not support our product candidate claims or may result in the discovery of adverse side effects.

Risks Associated with Our Intellectual Property and Technology Infrastructure

	●	We may not be able to protect or enforce the intellectual property rights for the technology used in, or expected to be used in, our products, which could impair our competitive position.

	●	We may be subject to intellectual property infringement claims by third parties which could be costly to defend, divert management’s attention and resources, and may result in liability.

	●	Competitors may violate the intellectual property rights for the technology used in, or expected to be used in, our products, and we may bring litigation to protect and enforce our intellectual property rights, which may result in substantial expense and may divert our attention from implementing our business strategy.

Risks Associated with Our Relationship with PAVmed

	●	PAVmed holds more voting stock than any of our other shareholders and thus it (or any successor to its stake in us), may have significant influence over certain actions requiring a stockholder vote.

	●	As a result of the exercise by the holder of PAVmed’s convertible debt and preferred stock of its rights under the agreements governing those instruments, such holder could acquire voting control of us.

	●	Certain conflicts of interest may arise between us and our affiliated companies, including PAVmed, and in some cases we have waived certain rights with respect thereto.

Risks Associated with Ownership of Our Common Stock

	●	Nasdaq may in the future delist our common stock, which could limit investors’ ability to make transactions in our securities and subject us to additional trading restrictions.

	●	Our stock price may be volatile, and holders of our common stock could incur substantial losses.

	●	Our outstanding options, convertible preferred stock and convertible notes, along with the potential issuance of shares under our equity compensation plans and other arrangements, may have an adverse effect on the market price of our common stock.

	●	We do not expect to pay any dividends in the foreseeable future.

Securities to Be Offered

This prospectus contains summary descriptions of the securities we may offer from time to time. These summary descriptions are not meant to be complete descriptions of each security. The particular terms of any security will be described in the applicable prospectus supplement.

RISK FACTORS

Any investment in our securities involves a high degree of risk. Before you make a decision to invest in our securities, you are urged to read and carefully consider the risks and uncertainties relating to an investment in our company set forth under “Risk Factors” in the prospectus supplement relating to a particular offering, together with all of the other information contained or incorporated by reference in this prospectus and the prospectus supplement. You should read and carefully consider the risks and uncertainties discussed under the item “Risk Factors” in our most recent annual report on Form 10-K and in any of our subsequent quarterly reports on Form 10-Q, as well as the other information in such reports and the risks, uncertainties and other information in the other documents we file with the SEC that are incorporated by reference in this prospectus and the prospectus supplement, as such reports and documents may be amended, supplemented or superseded from time to time by documents we subsequently file with the SEC or by the prospectus supplement relating to a particular offering. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business and results of operations. If any of these risks actually occur, our business, financial condition or results of operations could be seriously harmed. In that event, the market price for our common stock could decline and you may lose all or part of your investment.

USE OF PROCEEDS

Unless otherwise indicated in the applicable prospectus supplement, the net proceeds from the sale of the securities offered hereby will be used for working capital and other general corporate purposes. Any specific allocation of the net proceeds of an offering of securities to a specific purpose will be determined at the time of a particular offering and will be described in the prospectus supplement relating to such offering. Pending the application of such proceeds, we expect to invest the proceeds in short-term, interest bearing, investment-grade marketable securities or money market obligations.

DESCRIPTION OF CAPITAL STOCK

In the discussion that follows, we have summarized selected provisions of our certificate of incorporation, bylaws and the Delaware General Corporation Law, or the “DGCL,” relating to our capital stock. This summary is not complete, is subject to the relevant provisions of Delaware law and is qualified in its entirety by reference to our certificate of incorporation and our bylaws. You should read the provisions of our certificate of incorporation and our bylaws as currently in effect for provisions that may be important to you.

General

We are authorized to issue 300,000,000 shares of common stock, par value $0.001 per share, and 20,000,000 shares of preferred stock, par value $0.001 per share.

As of March 20, 2026, 176,945,972 shares of common stock were outstanding (inclusive of shares underlying unvested restricted stock awards) and 10,134 shares of preferred stock were outstanding. Of such shares of preferred stock, all of which were designated as Series B-1 Convertible Preferred Stock, or the “Series B-1 Preferred Stock.”

In addition, as of such date:

	●	12,353,542 shares of our common stock were issuable upon exercise of our outstanding stock options, at a weighted average exercise price of $1.57 per share;

	●	an estimated 16,823,761 shares of our common stock were issuable upon conversion of, and in payment of dividends on, the Series B-1 Preferred Stock, assuming that the Preferred Stock remains outstanding until its automatic conversion date and all dividends on the Preferred Stock payable in shares of our common stock are paid in full (without taking into account the beneficial ownership limitation set forth therein);

	●	13,294,267 shares of our common stock were issuable on March 13, 2026, upon conversion in full of, and in payment of final dividends on, the Series B Convertible Preferred Stock, or the “Series B Preferred Stock,” but are held in abeyance by us as a result of the beneficial limitations contained in the Series B Preferred Stock; and

	●	an estimated 36,975,000 shares of our common stock were issuable upon conversion of, and in payment of interest on, the 2024 Convertible Notes, assuming that the notes are converted in full on their maturity date and the maximum number of shares permitted under the notes to be issued in payment of interest are so issued (without taking into account the limitations on conversion set forth therein).

In addition, as of March 20, 2026, 876,335 shares of our common stock were reserved for issuance, but not subject to outstanding stock-based equity awards, under our Amended and Restated 2018 Long-Term Incentive Equity Plan, or the “2018 Plan,” and 1,904,371 shares of our common stock were reserved for issuance, but not yet issued, under our Employee Stock Purchase Plan, or the “ESPP.” The number of shares available under the 2018 Plan will automatically increase on January 1st of each year, through (and including) January 1, 2032, in an amount equal to 6% of the total number of shares of our common stock outstanding on December 31st of the preceding calendar year, unless our board of directors provides for a lesser amount. Similarly, the number of shares available for issuance under the ESPP will automatically increase on January 1st of each year, through (and including) January 1, 2032, in an amount equal to the lesser of (a) 2% of the total number of shares of our common stock outstanding on December 31st of the preceding calendar year, and (b) 1,000,000 shares, unless our board of directors provides for a lesser amount.

Common Stock

Holders of our common stock are entitled to one vote for each share held of record on all matters to be voted on by stockholders. There is no cumulative voting with respect to the election of directors, with the result that the holders of more than 50% of the shares voted for the election of directors can elect all of the directors. Subject to any preferential dividend rights of any outstanding shares of preferred stock, holders of common stock are entitled to receive dividends, if declared by our board of directors, out of funds that we may legally use to pay dividends. If we liquidate or dissolve, holders of common stock are entitled to share ratably in our assets once our debts and any liquidation preference owed to any then-outstanding preferred stockholders are paid. Our common stockholders have no conversion, preemptive or other subscription rights, and no liquidation preference, and there are no sinking fund or redemption provisions applicable to the common stock. All shares of common stock that are outstanding are fully-paid and non-assessable.

Preferred Stock

The Board has the authority, without further action by our stockholders, to issue shares of preferred stock in one or more series and to fix the rights, preferences, privileges, and restrictions thereof. These rights, preferences and privileges could include dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, and sinking fund terms, any or all of which may be greater than the rights of common stock. The issuance of preferred stock could adversely affect the voting power of holders of common stock and the likelihood that such holders will receive dividend payments and payments upon our liquidation. In addition, the issuance of preferred stock could have the effect of delaying, deferring or preventing a change in control of us or other corporate action.

Series B-1 Preferred Stock

The Series B-1 Preferred Stock is senior to our common stock and any other class of our capital stock that is not by its terms senior to or pari passu with the Series B-1 Preferred Stock. The Series B-1 Preferred Stock is a voting security (subject to applicable ownership limitations).

Each share of Series B-1 Preferred Stock is convertible at the option of the holder, subject to certain beneficial ownership limitations into such number of shares of our common stock, equal to the number of Series B-1 Preferred Shares to be converted, multiplied by the stated value of $1,000, divided by the conversion price in effect at the time of the conversion. The initial conversion price is $0.7228, subject to adjustment in the event of stock splits, stock dividends, and similar transactions. The Series B-1 Preferred Stock is convertible into shares of our common stock at any time at the option of the holder from and after the six-month anniversary of its issuance, and automatically converts into shares of our common stock on May 6, 2026, the second anniversary of its issuance at a conversion price of $0.7228.

Each holder of Series B-1 Preferred Stock (i) was entitled to receive, and did receive, a dividend on or about May 6, 2025 equal to 20% of the number of shares of common stock issuable upon conversion of the Series B-1 Preferred Stock then held by such holder on May 6, 2025, and (ii) will be entitled to receive a dividend on or about May 6, 2026 equal to a number of shares of common stock equal to 20% of the number of shares of common stock issuable upon conversion of the Series B-1 Preferred Stock then held by such holder on May 6, 2026. A holder that voluntarily converts its Series B-1 Preferred Stock prior to May 6, 2026 will not receive the dividend that accrues on such date with respect to such converted Series B-1 Preferred Stock. The holders of the Series B-1 Preferred Stock also will be entitled to dividends equal, on an as-if-converted to shares of common stock basis, to and in the same form as dividends actually paid on shares of the common stock when, as, and if such dividends are paid on shares of the common stock.

In the event of any voluntary or involuntary liquidation, dissolution or winding up of us (or any Deemed Liquidation Event as defined in the Certificate of Designation), the holders of shares of Series B-1 Preferred Stock then outstanding will be entitled to be paid out of our assets available for distribution to our stockholders, before any payment shall be made to the holders of common stock by reason of their ownership thereof, an amount per share equal to the greater of (i) the stated value, plus any dividends accrued but unpaid thereon, or (ii) such amount per share as would have been payable had all shares of Series B-1 Preferred Stock been converted into common stock immediately prior to such event.

We will not effect any conversion of the Series B-1 Preferred Stock, and a holder will not have the right to receive dividends or convert any portion of the Series B-1 Preferred Stock, to the extent that, after giving effect to the receipt of dividends or the conversion, the holder (together with such holder’s affiliates, and any persons acting as a group together with such holder or any of the holder’s affiliates) would beneficially own in excess of 4.99% of the outstanding common stock (or, upon election of the holder, 9.99% of the outstanding common stock).

We and the investors in the offering also executed a registration rights agreement, pursuant to which we agreed to file a registration statement covering the resale of the shares of common stock issuable pursuant to the Series B-1 Preferred Stock. We filed such registration statement on Form S-3 with the SEC (file number 333-280650), which filing became effective on July 18, 2024, covering the resale of the shares of common stock issuable pursuant to the Series B and Series B-1 Preferred Stock.

Dividends

We have not paid any cash dividends on our shares of common stock to date. The payment of cash dividends in the future will be dependent upon our revenues and earnings, if any, capital requirements and general financial condition and will be within the discretion of our board. It is the present intention of our board to retain all earnings, if any, for use in our business operations and, accordingly, our board does not anticipate declaring any dividends in the foreseeable future. In addition, the 2024 Convertible Notes contain customary restrictions on the payment of dividends on our common stock and the Preferred Stock is senior to the common stock in right of payment of dividends. We are also required to pay dividends on the Preferred Stock in shares of our common stock as described above.

Anti-Takeover Provisions

Some provisions of Delaware law, our certificate of incorporation and bylaws contain provisions that could make it more difficult to acquire us by means of a tender offer or a proxy contest or otherwise, or to remove our incumbent officers and directors.

These provisions of Delaware law, our certificate of incorporation and bylaws could have the effect of preventing changes in the composition of our board and management. These provisions may also have the effect of discouraging others from attempting hostile takeovers and, as a consequence, they may also inhibit temporary fluctuations in the market price of our common stock that often result from actual or rumored hostile takeover attempts. It is possible that these provisions could make it more difficult to accomplish or could deter transactions that stockholders may otherwise consider to be in their best interest or in our best interests, including transactions which provide for payment of a premium over the market price for our shares.

These provisions are intended to discourage coercive takeover practices and inadequate takeover bids. These provisions are also designed to encourage persons seeking to acquire control of us to first negotiate with our board. We believe that the benefits of the increased protection of our ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure us outweigh the disadvantages of discouraging these proposals because negotiation of these proposals could result in an improvement of their terms.

Delaware Anti-Takeover Statute

We are subject to Section 203 of the DGCL, which prohibits persons deemed to be “interested stockholders” from engaging in a “business combination” with a publicly held Delaware corporation for three years following the date these persons become interested stockholders unless the business combination is, or the transaction in which the person became an interested stockholder was, approved in a prescribed manner or another prescribed exception applies. Generally, an “interested stockholder” is a person who, together with affiliates and associates, owns, or within three years prior to the determination of interested stockholder status did own, 15% or more of a corporation’s voting stock. Generally, a “business combination” includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested stockholder. The existence of this provision may have an anti-takeover effect with respect to transactions not approved in advance by our board. A Delaware corporation may “opt out” of these provisions with an express provision in its original certificate of incorporation or an express provision in its certificate of incorporation or bylaws resulting from a stockholders’ amendment approved by at least a majority of the outstanding voting shares. We have not opted out of these provisions. As a result, mergers or other takeover or change in control attempts of us may be discouraged or prevented.

Undesignated Preferred Stock

The ability of our board, without action by the stockholders, to issue undesignated shares of preferred stock with voting or other rights or preferences as designated by our board could impede the success of any attempt to change control of us. These and other provisions may have the effect of deterring hostile takeovers or delaying changes in control or management of us.

Authorized Common Stock

Our authorized but unissued shares of common stock will be available for future issuance without stockholder approval. These additional shares may be utilized for a variety of corporate purposes, including future public offerings to raise additional capital and corporate acquisitions. The existence of authorized but unissued shares of common stock also could render more difficult or discourage an attempt to obtain control of a majority of our common stock by means of a proxy contest, tender offer, merger or otherwise.

Classified Board of Directors

Our board is divided into three classes. The number of directors in each class will be as nearly equal as possible. Directors elected to succeed those directors whose terms expire shall be elected for a term of office to expire at the third succeeding annual meeting of stockholders after their election. The existence of a classified board may extend the time required to make any change in control of our board when compared to a corporation with an unclassified board. It may take two annual meetings for our stockholders to effect a change in control of our board, because in general less than a majority of the members of our board will be elected at a given annual meeting. Because our board is classified and our certificate of incorporation does not otherwise provide, under Delaware law, our directors may only be removed for cause.

Vacancies on the Board

Our certificate of incorporation and bylaws provide that any vacancy occurring on our board, including by reason of removal of a director, and any newly created directorship may be filled only by a majority of the remaining directors in office. This system of appointing directors may discourage a third party from making a tender offer or otherwise attempting to obtain control of our company, because it generally makes it more difficult for stockholders to replace a majority of the directors.

Advance Notice Requirements for Stockholder Proposals and Director Nominations

Our bylaws provide advance notice procedures for stockholders seeking to bring business before our annual meeting of stockholders, or to nominate candidates for election as directors at any meeting of stockholders. Our bylaws also will specify certain requirements regarding the form and content of a stockholder’s notice. These provisions may preclude our stockholders from bringing matters before our annual meeting of stockholders or from making nominations for directors at our meetings of stockholders.

No Cumulative Voting; Special Meeting of Stockholders

Stockholders will not be permitted to cumulate their votes for the election of directors. Furthermore, special meetings of our stockholders may be called only by the Chief Executive Officer, the President, the board of directors, or a majority of our stockholders.

Exclusive Forum Selection

Our certificate of incorporation requires, to the fullest extent permitted by law, subject to limited exceptions, that derivative actions brought in our name, actions against directors, officers and employees for breach of fiduciary duty and other similar actions may be brought only in the Court of Chancery in the State of Delaware and, if brought outside of Delaware, the stockholder bringing the suit will be deemed to have consented to service of process on such stockholder’s counsel in any action brought to enforce the exclusive forum provision. Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and consented to the forum provisions in our certificate of incorporation.

Notwithstanding the foregoing, Section 27 of the Exchange Act creates exclusive federal jurisdiction over all suits brought to enforce any duty or liability created by the Exchange Act or the rules and regulations thereunder. In addition, Section 22 of the Securities Act creates concurrent jurisdiction for federal and state courts over all suits brought to enforce any duty or liability created by the Securities Act or the rules and regulations thereunder. As a result, the exclusive forum provision provides that the Court of Chancery and the federal district court for the District of Delaware will have concurrent jurisdiction over any action arising under the Securities Act or the rules and regulations thereunder, and the exclusive forum provision will not apply to suits brought to enforce any duty or liability created by the Exchange Act or the rules and regulations thereunder or any other claim for which the federal courts have exclusive jurisdiction. To the extent the exclusive forum provision restricts the courts in which our stockholders may bring claims arising under the Securities Act and the rules and regulations thereunder, there is uncertainty as to whether a court would enforce such provision. Investors cannot waive compliance with the federal securities laws and the rules and regulations promulgated thereunder.

Although we believe this provision benefits us by providing increased consistency in the application of Delaware law in the types of lawsuits to which it applies, a court may determine that this provision is unenforceable, and to the extent it is enforceable, the provision may have the effect of discouraging lawsuits against our directors and officers and increasing the cost to stockholders of bringing such lawsuits.

Listing

Our common stock is listed on the Nasdaq Capital Market under the symbol “LUCD.”

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Continental Stock Transfer & Trust Company located at 1 State Street, 30th Floor, New York, NY 10004.

Limitation of Directors’ Liability and Indemnification

The Delaware General Corporation Law authorizes corporations to limit or eliminate, subject to certain conditions, the personal liability of directors to corporations and their stockholders for monetary damages for breach of their fiduciary duties. Our amended and restated certificate of incorporation limits the liability of our directors to the fullest extent permitted by Delaware law.

We have purchased director and officer liability insurance to cover liabilities our directors and officers may incur in connection with their services to us, including matters arising under the Securities Act. Our amended and restated certificate of incorporation and by-laws also provide that we will indemnify all persons whom we have the power to indemnify under Delaware law, including our directors and officers, to the fullest extent permitted by Delaware law. In addition, we have entered into customary indemnification agreements with each of our officers and directors.

There is no pending litigation or proceeding involving any of our directors, officers, employees, or agents in which indemnification will be required or permitted. We are not aware of any threatened litigation or proceedings that may result in a claim for such indemnification.

Insofar as indemnification for liabilities arising under the Securities Act may be permitted to directors, officers or person controlling us pursuant to the foregoing provisions, we have been advised that in the opinion of the SEC such indemnification is against public policy as expressed in the Act and is therefore unenforceable.

DESCRIPTION OF DEBT SECURITIES

We may offer any combination of senior debt securities or subordinated debt securities. We may issue the debt securities under one or more indentures or without the use of an indenture to the extent such issuance without an indenture is exempt under the terms of the Trust Indenture Act of 1939, as amended. If we issue the debt securities under one or more indentures, the senior debt securities will be issued under one form of indenture and the subordinated debt securities will be issued under another form of indenture, in each case, between us, as issuer, and the trustee or trustees identified in a prospectus supplement. The form for each type of indenture is filed as an exhibit to the registration statement of which this prospectus is a part. Further information regarding the trustee or trustees may be provided in the prospectus supplement.

The following outlines some of the general terms and provisions of the debt securities that we may issue. A prospectus supplement will describe the particular terms of any debt securities offered from time to time, and may supplement or change the terms outlined below. If we issue the debt securities under an indenture, we will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, a form of the indenture supplement that sets forth the terms of the particular debt securities we are offering. If we issue the debt securities without an indenture, we will so file or incorporate by reference a form of the instrument evidencing the debt securities that sets forth such terms. The summary of such debt securities contained in this prospectus and in the applicable prospectus supplement is qualified in its entirety by reference to the indentures and the applicable indenture supplement, or to the other applicable instrument evidencing the debt securities. We urge you to read the indentures and the applicable indenture supplement, or the other applicable instrument evidencing the debt securities, and the additional description of the debt securities in the prospectus supplement.

General

Within the total dollar amount of this shelf registration statement, we may issue an unlimited principal amount of debt securities in separate series. We may specify a maximum aggregate principal amount for the debt securities of any series. However, the indentures, or other applicable instruments, might not limit the amount of other debt that we may incur or whether that debt is senior to the debt securities offered by this prospectus, and might not contain financial or similar restrictive covenants. The indentures, or other applicable instruments, might not contain any provision to protect holders of debt securities against a sudden or dramatic decline in our ability to pay our debt.

Senior debt securities will be unsubordinated obligations and will rank equal with all our other unsubordinated debt. Subordinated debt securities will be paid only if all payments due under our senior indebtedness, including any outstanding senior debt securities, have been made.

The prospectus supplement will describe the debt securities and the price or prices at which we will offer the debt securities. The description also will include:

	●	the title and form of the debt securities;

	●	any limit on the aggregate principal amount of the debt securities or the series of which they are a part;

	●	the date or dates on which we must repay the principal, the maturity date and the principal amount due at maturity and whether the securities will be offered at a price such that they will be deemed an “original issue discount”;

	●	the person to whom any interest on a debt security of the series will be paid;

	●	the rate or rates at which the debt securities will bear interest;

	●	if any, the date or dates from which interest will accrue, and the dates on which we must pay interest;

	●	the place or places where we must pay the principal and any premium or interest on the debt securities;

	●	the terms and conditions on which we may redeem any debt security, if at all;

	●	any obligation to redeem or purchase any debt securities, and the terms and conditions on which we must do so;

	●	the denominations in which we may issue the debt securities;

	●	the currency in which we will pay the principal of and any premium or interest on the debt securities and whether we may pay in property other than cash, including our securities;

	●	the principal amount of the debt securities that we will pay upon declaration of acceleration of their maturity;

	●	whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a United States person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

	●	if applicable, that the debt securities are defeasible and the terms of such defeasance;

	●	if applicable, the terms of any right to convert debt securities into, or exchange debt securities for, common stock, preferred stock. other debt securities and/or other securities or property;

	●	whether we will issue the debt securities in the form of one or more global securities and, if so, the respective depositaries for the global securities and the terms of the global securities;

	●	the subordination provisions that will apply to any subordinated debt securities;

	●	the events of default applicable to the debt securities and the rights of the trustee, if applicable, or the holders to declare the principal amount of any of the debt securities due and payable; and

	●	the covenants that will apply to the debt securities.

We may sell the debt securities at a substantial discount below their stated principal amount. We will describe U.S. federal income tax considerations, if any, applicable to debt securities sold at an original issue discount in the prospectus supplement. An “original issue discount security” is any debt security sold for less than its face value, and which provides that the holder cannot receive the full face value if maturity is accelerated. The prospectus supplement relating to any original issue discount securities will describe the particular provisions relating to acceleration of the maturity upon the occurrence of an event of default. In addition, we will describe U.S. federal income tax or other considerations applicable to any debt securities that are denominated in a currency or unit other than U.S. dollars in the prospectus supplement. If we issue debt securities at a discount from their stated principal amount, then, for purposes of calculating the aggregate offering price of the offered securities issued under this prospectus, we will include only the offering price of the debt securities and not the principal amount of the debt securities.

The prospectus supplement will describe, if applicable, the terms on which you may convert debt securities into or exchange them for common stock, preferred stock, other debt securities and/or other securities or property. The conversion or exchange may be mandatory or may be at our option or at your option. The prospectus supplement will describe how the number of shares of preferred stock and common stock or amount of debt securities or other securities or property to be received upon conversion or exchange would be calculated.

The Indentures

The following outlines some of the general terms and provisions of the indentures for senior debt securities and subordinated debt securities issued under the indentures. Forms of the indentures are filed as exhibits to the registration statement of which this prospectus is a part. The summary of the indentures contained in this prospectus is qualified in its entirety by reference to such forms, which we urge you to read in full.

Subordinated Debt Securities

The indebtedness underlying any subordinated debt securities will be payable only if all payments due under our senior indebtedness, as defined in the applicable indenture and any indenture supplement, including any outstanding senior debt securities, have been made. If we distribute our assets to creditors upon any dissolution, winding-up, liquidation or reorganization or in bankruptcy, insolvency, receivership or similar proceedings, we must first pay all amounts due or to become due on all senior indebtedness before we pay the principal of, or any premium or interest on, the subordinated debt securities. In the event the subordinated debt securities are accelerated because of an event of default, we may not make any payment on the subordinated debt securities until we have paid all senior indebtedness or the acceleration is rescinded. If the payment of subordinated debt securities accelerates because of an event of default, we must promptly notify holders of senior indebtedness of the acceleration.

If we experience a bankruptcy, dissolution or reorganization, holders of senior indebtedness may receive more, ratably, and holders of subordinated debt securities may receive less, ratably, than our other creditors. The indenture for subordinated debt securities may not limit our ability to incur additional senior indebtedness.

Form, Exchange and Transfer

We will issue debt securities only in fully registered form, without coupons, and only in denominations of $1,000 and integral multiples thereof, unless the prospectus supplement provides otherwise. The holder of a debt security may elect, subject to the terms of the indentures and the limitations applicable to global securities, to exchange them for other debt securities of the same series of any authorized denomination and of similar terms and aggregate principal amount.

Holders of debt securities may present them for exchange as provided above or for registration of transfer, duly endorsed or with the form of transfer duly executed, at the office of the transfer agent we designate for that purpose. We will not impose a service charge for any registration of transfer or exchange of debt securities, but we may require a payment sufficient to cover any tax or other governmental charge payable in connection with the transfer or exchange. We will name the transfer agent in the prospectus supplement. We may designate additional transfer agents or rescind the designation of any transfer agent or approve a change in the office through which any transfer agent acts, but we must maintain a transfer agent in each place where we will make payment on debt securities.

If we redeem the debt securities, we will not be required to issue, register the transfer of or exchange any debt security during a specified period prior to mailing a notice of redemption. We are not required to register the transfer of or exchange of any debt security selected for redemption, except the unredeemed portion of the debt security being redeemed.

Global Securities

The debt securities may be represented, in whole or in part, by one or more global securities that will have an aggregate principal amount equal to that of all debt securities of that series. Each global security will be registered in the name of a depositary identified in the prospectus supplement. We will deposit the global security with the depositary or a custodian, and the global security will bear a legend regarding the restrictions on exchanges and registration of transfer.

No global security may be exchanged in whole or in part for debt securities registered, and no transfer of a global security in whole or in part may be registered, in the name of any person other than the depositary or any nominee or successor of the depositary unless:

	●	the depositary is unwilling or unable to continue as depositary; or

	●	the depositary is no longer in good standing under the Securities Exchange Act of 1934, as amended, or “Exchange Act,” or other applicable statute or regulation.

The depositary will determine how all securities issued in exchange for a global security will be registered.

As long as the depositary or its nominee is the registered holder of a global security, we will consider the depositary or the nominee to be the sole owner and holder of the global security and the underlying debt securities. Except as stated above, owners of beneficial interests in a global security will not be entitled to have the global security or any debt security registered in their names, will not receive physical delivery of certificated debt securities and will not be considered to be the owners or holders of the global security or underlying debt securities. We will make all payments of principal, premium and interest on a global security to the depositary or its nominee. The laws of some jurisdictions require that some purchasers of securities take physical delivery of such securities in definitive form. These laws may prevent you from transferring your beneficial interests in a global security.

Only institutions that have accounts with the depositary or its nominee and persons that hold beneficial interests through the depositary or its nominee may own beneficial interests in a global security. The depositary will credit, on its book-entry registration and transfer system, the respective principal amounts of debt securities represented by the global security to the accounts of its participants. Ownership of beneficial interests in a global security will be shown only on, and the transfer of those ownership interests will be effected only through, records maintained by the depositary or any such participant.

The policies and procedures of the depositary may govern payments, transfers, exchanges and other matters relating to beneficial interests in a global security. We and the trustee will assume no responsibility or liability for any aspect of the depositary’s or any participant’s records relating to, or for payments made on account of, beneficial interests in a global security.

Payment and Paying Agents

We will pay principal and any premium or interest on a debt security to the person in whose name the debt security is registered at the close of business on the regular record date for such interest.

We will pay principal and any premium or interest on the debt securities at the office of our designated paying agent. Unless the prospectus supplement indicates otherwise, the corporate trust office of the trustee will be the paying agent for the debt securities.

Any other paying agents we designate for the debt securities of a particular series will be named in the prospectus supplement. We may designate additional paying agents, rescind the designation of any paying agent or approve a change in the office through which any paying agent acts, but we must maintain a paying agent in each place of payment for the debt securities.

The paying agent will return to us all money we pay to it for the payment of the principal, premium or interest on any debt security that remains unclaimed for a specified period. Thereafter, the holder may look only to us for payment, as an unsecured general creditor.

Consolidation, Merger and Sale of Assets

Under the terms of the indentures, so long as any securities remain outstanding, we may not consolidate or enter into a share exchange with or merge into any other person, in a transaction in which we are not the surviving corporation, or sell, convey, transfer or lease our properties and assets substantially as an entirety to any person, unless:

	●	the successor assumes our obligations under the debt securities and the indentures; and

	●	we meet the other conditions described in the indentures.

Events of Default

Each of the following will constitute an event of default under each indenture:

	●	failure to pay any interest on any debt security when due, for more than a specified number of days past the due date;

	●	failure to pay any principal or deposit any sinking fund payment when due;

	●	failure to perform any covenant or agreement in the indenture that continues for a specified number of days after written notice has been given by the trustee or the holders of a specified percentage in aggregate principal amount of the debt securities of that series;

	●	events of bankruptcy, insolvency or reorganization; and

	●	any other event of default specified in the prospectus supplement.

If an event of default occurs and continues, both the trustee and holders of a specified percentage in aggregate principal amount of the outstanding securities of that series may declare the principal amount of the debt securities of that series to be immediately due and payable. The holders of a majority in aggregate principal amount of the outstanding securities of that series may rescind and annul the acceleration if all events of default, other than the nonpayment of accelerated principal, have been cured or waived.

Except for its duties in case of an event of default, the trustee will not be obligated to exercise any of its rights or powers at the request or direction of any of the holders, unless the holders have offered the trustee reasonable indemnity. If they provide this indemnification and subject to conditions specified in the applicable indenture, the holders of a majority in aggregate principal amount of the outstanding securities of any series may direct the time, method and place of conducting any proceeding for any remedy available to the trustee or exercising any trust or power conferred on the trustee with respect to the debt securities of that series.

No holder of a debt security of any series may institute any proceeding with respect to the indentures, or for the appointment of a receiver or a trustee, or for any other remedy, unless:

●

the holder has previously given the trustee written notice of a continuing event of default;

	●	the holders of a specified percentage in aggregate principal amount of the outstanding securities of that series have made a written request upon the trustee, and have offered reasonable indemnity to the trustee, to institute the proceeding;

	●	the trustee has failed to institute the proceeding for a specified period of time after its receipt of the notification; and

	●	the trustee has not received a direction inconsistent with the request within a specified number of days from the holders of a specified percentage in aggregate principal amount of the outstanding securities of that series.

Modification and Waiver

We and the trustee may change an indenture without the consent of any holders with respect to specific matters, including:

	●	to fix any ambiguity, defect or inconsistency in the indenture; and

	●	to change anything that does not materially adversely affect the interests of any holder of debt securities of any series.

In addition, under the indentures, the rights of holders of a series of notes may be changed by us and the trustee with the written consent of the holders of at least a majority in aggregate principal amount of the outstanding debt securities of each series that is affected. However, we and the trustee may only make the following changes with the consent of the holder of any outstanding debt securities affected:

	●	extending the fixed maturity of the series of notes;

	●	reducing the principal amount, reducing the rate of or extending the time of payment of interest, or any premium payable upon the redemption, of any debt securities; or

	●	reducing the percentage of debt securities the holders of which are required to consent to any amendment.

The holders of a majority in principal amount of the outstanding debt securities of any series may waive any past default under the indenture with respect to debt securities of that series, except a default in the payment of principal, premium or interest on any debt security of that series or in respect of a covenant or provision of the indenture that cannot be amended without each holder’s consent.

Except in limited circumstances, we may set any day as a record date for the purpose of determining the holders of outstanding debt securities of any series entitled to give or take any direction, notice, consent, waiver or other action under the indentures. In limited circumstances, the trustee may set a record date. To be effective, the action must be taken by holders of the requisite principal amount of such debt securities within a specified period following the record date.

Defeasance

To the extent stated in the prospectus supplement, we may elect to apply the provisions in the indentures relating to defeasance and discharge of indebtedness, or to defeasance of restrictive covenants, to the debt securities of any series. The indentures provide that, upon satisfaction of the requirements described below, we may terminate all of our obligations under the debt securities of any series and the applicable indenture, known as legal defeasance, other than our obligation:

	●	to maintain a registrar and paying agents and hold monies for payment in trust;

	●	to register the transfer or exchange of the notes; and

	●	to replace mutilated, destroyed, lost or stolen notes.

In addition, we may terminate our obligation to comply with any restrictive covenants under the debt securities of any series or the applicable indenture, known as covenant defeasance.

We may exercise our legal defeasance option even if we have previously exercised our covenant defeasance option. If we exercise either defeasance option, payment of the notes may not be accelerated because of the occurrence of events of default.

To exercise either defeasance option as to debt securities of any series, we must irrevocably deposit in trust with the trustee money and/or obligations backed by the full faith and credit of the United States that will provide money in an amount sufficient in the written opinion of a nationally recognized firm of independent public accountants to pay the principal of, premium, if any, and each installment of interest on the debt securities. We may only establish this trust if, among other things:

	●	no event of default shall have occurred or be continuing;

	●	in the case of legal defeasance, we have delivered to the trustee an opinion of counsel to the effect that we have received from, or there has been published by, the Internal Revenue Service a ruling or there has been a change in law, which in the opinion of our counsel, provides that holders of the debt securities will not recognize gain or loss for federal income tax purposes as a result of such deposit, defeasance and discharge and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit, defeasance and discharge had not occurred;

	●	in the case of covenant defeasance, we have delivered to the trustee an opinion of counsel to the effect that the holders of the debt securities will not recognize gain or loss for federal income tax purposes as a result of such deposit, defeasance and discharge and will be subject to federal income tax on the same amount, in the same manner and at the same times as would have been the case if such deposit, defeasance and discharge had not occurred; and

	●	we satisfy other customary conditions precedent described in the applicable indenture.

Title

We may treat the person in whose name a debt security is registered as the absolute owner, whether or not such debt security may be overdue, for the purpose of making payment and for all other purposes.

Governing Law

The indentures and the debt securities will be governed by and construed in accordance with the laws of the State of New York.

DESCRIPTION OF WARRANTS

We may issue warrants for the purchase of common stock, preferred stock, debt securities or any other security offered hereby. Warrants may be issued in one or more series and may be issued independently or together with other securities and may be attached to or separate from any offered securities. We may issue the warrants directly or under warrant agreements to be entered into between a warrant agent and us. Any warrant agent will act solely as our agent in connection with the warrants and will not have any obligation or relationship of agency or trust for or with any holders or beneficial owners of warrants.

The following outlines some of the general terms and provisions of the warrants that we may issue. A prospectus supplement will describe the particular terms of any warrants offered from time to time, and may supplement or change the terms outlined below. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, a form of the warrant or form of the warrant agreement and warrant certificate that sets forth the terms of the particular warrants we are offering. The summary of such terms contained in this prospectus and in the applicable prospectus supplement is qualified in its entirety by reference to such warrant or warrant agreement and warrant certificate. We urge you to read the warrant or warrant agreement and warrant certificate and the additional description of the terms of the warrants included in the prospectus supplement.

The prospectus supplement relating to a particular issue of warrants will describe the terms of the warrants, including the following:

	●	the title of the warrants;

	●	the offering price for the warrants, if any;

	●	the aggregate number of the warrants;

	●	the designation and terms of the common stock, preferred stock or other class of security that may be purchased upon exercise of the warrants;

	●	if applicable, the designation and terms of the securities that the warrants are issued with and the number of warrants issued with each security;

	●	if applicable, the date from and after which the warrants and any securities issued with the warrants will be separately transferable;

	●	the number of shares and price of common stock or preferred stock, or the designation and number or amount of debt or other securities, that may be purchased upon exercise of a warrant;

	●	the dates on which the right to exercise the warrants commence and expire;

	●	if applicable, the minimum or maximum amount of the warrants that may be exercised at any one time;

	●	if applicable, a discussion of material U.S. federal income tax considerations;

	●	anti-dilution provisions of the warrants, if any;

	●	redemption or call provisions, if any, applicable to the warrants; and

	●	any additional terms of the warrants, including terms, procedures and limitations relating to the exchange and exercise of the warrants.

In the case of warrants issued under a warrant agreement, we and the warrant agent generally may amend or supplement the warrant agreement for a series of warrants without the consent of the holders of the warrants issued thereunder to effect changes that are not inconsistent with the provisions of the warrants and that do not materially and adversely affect the interests of the holders of the warrants.

Holders may exercise warrants as set forth in the prospectus supplement relating to the warrants being offered. In general, holders may exercise warrants at any time up to the close of business on the expiration date set forth in the applicable prospectus supplement. After the expiration time, unexercised warrants will be void.

Until a holder exercises the warrants to purchase any securities underlying the warrants, the holder will not have any rights as a holder of the underlying securities by virtue of ownership of warrants.

DESCRIPTION OF THE UNITS

We may issue units comprised of one or more of the other classes of securities offered hereby in any combination. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security.

The units may be, but are not required to be, issued under unit agreements to be entered into between us and a unit agent, as detailed in the prospectus supplement relating to the units being offered. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, a form of the unit agreement and unit certificate, if any, that sets forth the terms of the particular units we are offering. The summary of such terms contained in this prospectus and in the applicable prospectus supplement is qualified in its entirety by reference to such unit agreement and unit certificate. We urge you to read the unit agreement and unit certificate, if any, and the additional description of the terms of the units included in the prospectus supplement.

The prospectus supplement will describe the units and the price or prices at which we will offer the units. The description will include:

	●	the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances the securities comprising the units may be held or transferred separately;

	●	a description of the terms of any unit agreement governing the units;

	●	a description of the provisions for the payment, settlement, transfer or exchange of the units;

	●	a discussion of material federal income tax considerations, if applicable; and

	●	whether the units if issued as a separate security will be issued in fully registered or global form.

The descriptions of the units in this prospectus and in any prospectus supplement are summaries of the material provisions of the applicable agreements.

PLAN OF DISTRIBUTION OF SECURITIES

We may sell or issue the securities offered by this prospectus from time to time in any one or more of the following ways:

	●	through underwriters or dealers;

	●	through agents;

	●	directly to purchasers or a single purchaser; or

	●	through a combination of any of these methods.

The manner in which we may sell some or all of the securities covered by this prospectus includes, without limitation, through:

	●	a rights offering;

	●	exercises of warrants or other rights;

	●	an “at the market offering,” within the meaning of Rule 415(a)(4) of the Securities Act, to or through a market maker or into an existing trading market on an exchange or otherwise;

	●	a block trade in which a broker-dealer will attempt to sell as agent, but may position or resell a portion of the block, as principal, in order to facilitate the transaction;

	●	purchases by a broker-dealer, as principal, and resale by the broker-dealer for its account;

	●	ordinary brokerage transactions and transactions in which a broker solicits purchasers; and

	●	privately negotiated transactions.

The distribution of the securities may be effected from time to time in one or more transactions:

	●	at a fixed price, or prices, which may be changed from time to time;

	●	at market prices prevailing at the time of sale;

	●	at varying prices determined at the time of sale; or

	●	at negotiated prices.

For each offering of securities hereunder, we will describe the method of distribution of such securities, among other things, in a prospectus supplement. A prospectus supplement will set forth the terms of the offering of the securities, including:

	●	the name or names of any agents or underwriters;

	●	the purchase price of the securities being offered and the proceeds we will receive from the sale;

	●	any over-allotment options under which underwriters may purchase additional securities from us;

	●	any agency fees or underwriting discounts and other items constituting agents’ or underwriters’ compensation;

	●	any initial public offering price;

	●	any discounts or concessions allowed or reallowed or paid to dealers; and

	●	any securities exchanges or markets on which such securities may be listed.

Sales Through Underwriters or Dealers

If underwriters are used in the sale of the securities, the securities will be acquired by the underwriters for their own account and may be resold from time to time in one or more transactions. The securities may be either offered to the public through underwriting syndicates represented by managing underwriters or by underwriters without a syndicate. Unless otherwise set forth in the applicable prospectus supplement, the obligations of the underwriters to purchase the securities will be subject to certain conditions precedent and the underwriters will be obligated to purchase all of the securities if any are purchased. Any initial public offering price and any discounts or concessions allowed or paid to dealers may be changed from time to time.

If a dealer is used in the sale of the securities, we will sell such securities to the dealer, as principal. The dealer may then resell such securities to the public at varying prices to be determined by such dealer at the time of resale. We may negotiate and pay dealers’ commissions, discounts or concessions for their services. Any such dealer may be deemed to be an underwriter, as such term is defined in the Securities Act, of our securities so offered and sold.

Direct Sales and Sales Through Agents

We may sell the securities directly, in which case no underwriters or agents would be involved, or we may sell the securities through agents designated by us from time to time. If agents are used in the sale of the securities, the agent will not purchase any securities for its own account, but will arrange for the sale of the securities. Unless otherwise indicated in the prospectus supplement, any agent will be acting on a best efforts basis for the period of its appointment. We may negotiate and pay agent’s fees or commissions for their services. If the securities are sold directly by us, we may sell the securities to institutional investors or others who may be deemed to be underwriters within the meaning of the Securities Act, with respect to any sale of those securities.

Delayed Delivery Contracts

We may authorize underwriters, dealers or agents to solicit offers by institutional investors, such as commercial banks and investment companies, to purchase the securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. The conditions to these contracts and the commissions payable for solicitation of the contracts will be set forth in the applicable prospectus supplement.

At-the-Market Offerings

Underwriters, dealers or agents could make sales in an “at-the-market” offering, directly on the Nasdaq Capital Market, the existing trading market for our common stock, or such other exchange or automated quotation system on which our securities trade, or to or through a market maker other than on an exchange.

Rights Offerings

We may issue the securities as a dividend or distribution or in a subscription rights offering to our existing security holders. If we offer securities in a subscription rights offering to our existing security holders, we may enter into a standby underwriting agreement with dealers, acting as standby underwriters. We may pay the standby underwriters a commitment fee for the securities they commit to purchase on a standby basis. If we do not enter into a standby underwriting arrangement, we may retain a dealer-manager to manage a subscription rights offering for us.

Compensation

In compliance with the guidelines of the Financial Industry Regulatory Authority, Inc., or FINRA, all discounts, commissions or agency fees or other items constituting underwriting compensation to be received by any FINRA member or independent broker-dealer will be disclosed in the applicable prospectus supplement.

Indemnification

Any underwriters and agents may be entitled to indemnification by us against certain civil liabilities, including liabilities under the Securities Act, or to contribution with respect to payments which the agents or underwriters may be required to make in respect of their liabilities.

Stabilization Activities

During and after an offering through underwriters, the underwriters may purchase and sell the securities in the open market. These transactions may include over allotment and stabilizing transactions and purchases to cover syndicate short positions created in connection with the offering. The underwriters may also impose a penalty bid, whereby selling concessions allowed to syndicate members or other broker-dealers for the offered securities sold for their account may be reclaimed by the syndicate if such offered securities are repurchased by the syndicate in stabilizing or covering transactions. These activities may stabilize, maintain or otherwise affect the market price of the offered securities, which may be higher than the price that might otherwise prevail in the open market. If commenced, these activities may be discontinued at any time.

Passive Market Making

Any underwriters who are qualified market makers may engage in passive market making transactions in the securities in accordance with Rule 103 of Regulation M.

Trading Markets

Unless otherwise specified in the applicable prospectus supplement, securities offered under this prospectus will be a new issue and, other than the common stock, which is quoted on the Nasdaq Capital Market, will have no established trading market. We may elect to list any other class or series of securities on an exchange, and in the case of the common stock, on any additional exchange, but, unless otherwise specified in the applicable prospectus supplement, we shall not be obligated to do so. Any underwriters to whom securities are sold for public offering and sale may make a market in the securities, but the underwriters will not be obligated to do so and may discontinue any market making at any time without notice. The securities may or may not be listed on a national securities exchange or a foreign securities exchange. No assurance can be given as to the liquidity of the trading market for any of the securities.

Other Matters

Any underwriters, dealers and agents, and their associates and affiliates may be customers of, have borrowing relationships with, engage in other transactions with, or perform services, including investment banking services, for us or one or more of our respective affiliates in the ordinary course of business.

We will bear all costs, expenses and fees associated with the registration of the securities offered.

LEGAL MATTERS

The legality of the securities offered by this prospectus has been passed upon by Graubard Miller, New York, New York.

EXPERTS

The consolidated financial statements of Lucid Diagnostics Inc. and Subsidiaries as of December 31, 2025 and for the year then ended, which are incorporated in this prospectus by reference to the Annual Report on Form 10-K for the year ended December 31, 2025, have been so incorporated in reliance on the report of CBIZ CPAs P.C., an independent registered public accounting firm (which report includes an explanatory paragraph as to the Company’s ability to continue as a going concern), given on the authority of said firm as experts in auditing and accounting.

WHERE YOU CAN FIND MORE INFORMATION

We have filed with the SEC a registration statement under the Securities Act relating to the offering of these securities. The registration statement, including the attached exhibits, contains additional relevant information about us and the securities. This prospectus does not contain all of the information set forth in the registration statement. You can obtain a copy of the registration statement, at prescribed rates, from the SEC at the address listed above.

Statements contained in this prospectus regarding the contents of any contract or other document that is filed as an exhibit to the registration statement or any SEC filing incorporated by reference in the registration statement are not necessarily complete, and each such statement is qualified in all respects by reference to the full text of such contract or other document filed as an exhibit to the registration statement or any SEC filing incorporated by reference in the registration statement.

The registration statement and our SEC filings, including the documents referred to below under “Information Incorporated by Reference,” are also available on our website, www.luciddx.com. We have not incorporated by reference into this prospectus the information on our website, and you should not consider it to be a part of this prospectus.

INFORMATION INCORPORATED BY REFERENCE

The SEC allows us to incorporate by reference the information we file with it, which means that we can disclose important information to you by referring you to those documents. The information incorporated by reference is an important part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. This prospectus incorporates by reference the documents listed below, all filings we make under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, or the “Exchange Act,” after the initial filing date of the registration statement of which this prospectus forms a part and prior to effectiveness of such registration statement, and all filings we make with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act after effectiveness of such registration statement and prior to the sale of all of the securities offered hereby:

	●	Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (filed on March 25, 2026).

	●	Form 8-A filed on October 12, 2021 registering our common stock under Section 12(b) of the Exchange Act, as updated by Exhibit 4.1 to our Annual Report on Form 10-K for the fiscal year ended December 31, 2025 (filed on March 25, 2026).

Any statement contained in a document filed before the date of this prospectus and incorporated by reference herein shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained herein modifies or supersedes such statement. Any statement so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus. Any information that we file after the date of this prospectus with the SEC and incorporated by reference herein will automatically update and supersede the information contained in this prospectus and in any document previously incorporated by reference in this prospectus. Notwithstanding the foregoing, we are not incorporating any document or portion thereof or information deemed to have been furnished and not filed in accordance with SEC rule.

We will provide you with a copy of the documents incorporated by reference in this prospectus, without charge, upon written or oral request directed to Lucid Diagnostics Inc., 360 Madison Avenue 25^th Floor, New York, New York 10017, telephone number (917) 813-1828. You may also access the documents incorporated by reference as described under “Where You Can Find More Information.”

18,000,000 Shares

Lucid Diagnostics Inc.

Common Stock

PROSPECTUS SUPPLEMENT

Joint Bookrunners

Canaccord Genuity

BTIG

April 23, 2026

SEC Form 424B5 filed by Lucid Diagnostics Inc.