Shuttle Pharmaceuticals Holdings, Inc.

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 10-K

(Mark One)

For the fiscal year ended December 31,2025

or

For the transition period from ______________ to ______________

Commission file number:001-41488

(Exact name of registrant as specified in its charter)

401 Professional Drive, Suite 260

Gaithersburg, MD 20879

(Address of principal executive offices) (Zip Code)

(240) 403-4212

Registrant’s telephone number, including area code

Securities registered pursuant to Section 12(b) of the Act:

Securities registered pursuant to section 12(g) of the Act: NONE

Indicate by check mark if the registrant is a well-known seasoned issuer, as defined in Rule 405 of the Securities Act. Yes ☐No ☒

Indicate by check mark if the registrant is not required to file reports pursuant to Section 13 or Section 15(d) of the Act. Yes ☐No ☒

Indicate by check mark whether the registrant (1) has filed all reports required to be filed by Section 13 or 15(d) of the Securities Exchange Act of 1934 during the preceding 12 months (or for such shorter period that the registrant was required to file such reports), and (2) has been subject to such filing requirements for the past 90 days. Yes ☒ No ☐

Indicate by check mark whether the registrant has submitted electronically every Interactive Data File required to be submitted pursuant to Rule 405 of Regulation S-T (§ 232.405 of this chapter) during the preceding 12 months (or for such shorter period that the registrant was required to submit such files). Yes ☒ No ☐

Indicate by check mark whether the registrant is a large accelerated filer, an accelerated filer, a non-accelerated filer, a smaller reporting company, or an emerging growth company. See the definitions of “large accelerated filer,” “accelerated filer,” “smaller reporting company” and “emerging growth company” in Rule 12b-2 of the Exchange Act.

If an emerging growth company, indicate by check mark if the registrant has elected not to use the extended transition period for complying with any new or revised financial accounting standards provided pursuant to Section 13(a) of the Exchange Act.☐

Indicate by check mark whether the registrant has filed a report on and attestation to its management’s assessment of the effectiveness of its internal control over financial reporting under Section 404(b) of the Sarbanes-Oxley Act (15 U.S.C. 7262(b)) by the registered public accounting firm that prepared or issued its audit report.☐

If securities are registered pursuant to Section 12(b) of the Act, indicate by check mark whether the financial statements of the registrant included in the filing reflect the correction of an error to previously issued financial statements.☐

Indicate by check mark whether any of those error corrections are restatements that required a recovery analysis of incentive-based compensation received by any of the registrant’s executive officers during the relevant recovery period pursuant to §240.10D-1(b). ☐

Indicate by check mark whether the registrant is a shell company (as defined in Rule 12b-2 of the Act). Yes ☐ No☒

The aggregate market value of the registrant’s common stock, par value $0.00001 per share, held by non-affiliates of the registrant, as computed by reference to the June 30, 2025 closing price reported by Nasdaq, was approximately$4,744,078.

The number of shares outstanding of the registrant’s common stock on March 24, 2026, was 5,591,290.

DOCUMENTS INCORPORATED BY REFERENCE

Specified portions of the registrant’s definitive Proxy Statement to be issued in conjunction with the registrant’s 2026 Annual Meeting of Shareholders, which is expected to be filed not later than 120 days after the registrant’s fiscal year ended December 31, 2025, are incorporated by reference into Part III of this Annual Report. Except as expressly incorporated by reference, the registrant’s Proxy Statement shall not be deemed to be a part of this Annual Report on Form 10-K.

TABLE OF CONTENTS

FORWARD LOOKING STATEMENTS

This Annual Report on Form 10-K (including the section regarding Management’s Discussion and Analysis of Results of Operations, the “Annual Report”) contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, or the Securities Act, and Section 21E of the Securities Exchange Act of 1934, as amended, or the Exchange Act. These statements are based on our management’s beliefs and assumptions and on information currently available to our management. Although we believe that the expectations reflected in these forward-looking statements are reasonable, these statements relate to future events or our future financial performance, and involve known and unknown risks, uncertainties and other factors that may cause our actual results, levels of activity, performance or achievements to be materially different from any future results, levels of activity, performance or achievements expressed or implied by these forward-looking statements. All statements other than statements of historical facts contained in this Annual Report are forward-looking statements. In some cases, you can identify forward-looking statements by terminology such as “may,” “could,” “will,” “would,” “should,” “expect,” “plan,” “anticipate,” “believe,” “estimate,” “intend,” “predict,” “seek,” “contemplate,” “project,” “continue,” “potential,” “ongoing” or the negative of these terms or other comparable terminology. These forward-looking statements include, but are not limited to, statements about:

You should not place undue reliance on forward-looking statements, because they involve known and unknown risks, uncertainties, and other factors, which are, in some cases, beyond our control and which could materially affect results. Factors that may cause actual results to differ materially from current expectations include, among other things, those listed in the section titled “Risk Factors” in this Annual Report, and in our other filings with the Securities and Exchange Commission (the “SEC”). Actual events or results may vary significantly from those implied or projected by the forward-looking statements due to these risk factors. No forward-looking statement is a guarantee of future performance. You should read this Annual Report, the documents that we reference in this Annual Report and the documentation we have filed as exhibits thereto with the SEC, with the understanding that our actual future results and circumstances may be materially different from what we expect.

Unless the context otherwise requires, the terms “the Company,” “Shuttle Pharma,” “we,” “us,” and “our” in this Annual Report refer to Shuttle Pharmaceuticals Holdings, Inc. and its subsidiaries.

Summary Risk Factors

The risks described under the heading “Risk Factors” beginning on page 8 of this Annual Report may cause us not to realize the full benefits of our strengths and/or may cause us to be unable to successfully execute all or part of our strategy. Some of the more significant challenges we face include: