Exhibit 3.1

Certificate of Amendment

CERTIFICATE OF AMENDMENT TO THE

AMENDED AND RESTATED CERTIFICATE OF INCORPORATION

DECOY THERAPEUTICS INC.

Decoy Therapeutics Inc., a corporation organized and existing under and by virtue of the General Corporation Law of the State of Delaware (the “Corporation”), does hereby certify as follows:

FIRST: The name of the Corporation is Decoy Therapeutics Inc., and the Corporation was originally incorporated pursuant to the DGCL on February 26, 2014 (as subsequently amended, the “Certificate of Incorporation”), under the name Flex Pharma, Inc.

SECOND: Article IV.A of the Certificate of Incorporation is amended and restated in its entirety to read as follows:

This Company is authorized to issue two classes of stock to be designated, respectively, “Common Stock” and “Preferred Stock.” The total number of shares which the Company is authorized to issue is 110,000,000 shares. 100,000,000 shares shall be Common Stock, each having a par value of $0.0001. 10,000,000 shares shall be Preferred Stock, each having a par value of $0.0001.

Upon the filing and effectiveness (the “Effective Time”) of this amendment to the Corporation’s Amended and Restated Certificate of Incorporation, as amended, pursuant to the Delaware General Corporation Law, each 12 shares of Common Stock issued immediately prior to the Effective Time (the “Old Common Stock”) shall be reclassified and combined into one validly issued, fully paid and non-assessable share of the Corporation’s common stock, $0.0001 par value per share (the “New Common Stock”), without any action by the holder thereof (the “Reverse Stock Split”) and without increasing or decreasing the authorized number of shares of Common Stock or Preferred Stock. No fractional shares of New Common Stock shall be issued as a result of the Reverse Stock Split and, in lieu thereof, upon surrender after the Effective Time of a certificate or book entry position which formerly represented shares of Old Common Stock that were issued and outstanding immediately prior to the Effective Time, any person who would otherwise be entitled to a fractional share of New Common Stock as a result of the Reverse Stock Split, following the Effective Time, shall be entitled to receive a cash payment equal to the fraction of a share of New Common Stock to which such holder would otherwise be entitled multiplied by the closing price per share of the New Common Stock on the Nasdaq Capital Market at the close of business on the date of the Effective Time. Each certificate that theretofore represented shares of Old Common Stock shall thereafter represent that number of shares of New Common Stock into which the shares of Old Common Stock represented by such certificate shall have been reclassified and combined; provided, that each person holding of record a stock certificate or certificates that represented shares of Old Common Stock shall receive, upon surrender of such certificate or certificates, a new certificate or certificates evidencing and representing the number of shares of New Common Stock to which such person is entitled under the foregoing reclassification and combination.

3. This Certificate of Amendment has been duly adopted by the Board of Directors and stockholders of the Corporation in accordance with Section 242 of the General Corporation Law of the State of Delaware.

4. This Certificate of Amendment shall become effective as of 5:00 p.m., Eastern Time on March 6, 2026.

[Signature page follows]

Exhibit 3.1

IN WITNESS WHEREOF, the Corporation has caused its duly authorized officer to execute this Certificate of Amendment on this 5th day of March, 2026.



DECOY THERAPEUTICS INC.

By:		/s/ Mark Rosenblum
Name:		Mark Rosenblum
Title:		Executive Vice President and Chief Financial Officer

Decoy Therapeutics Inc. 8-K