Sagimet Biosciences Inc.

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AVAILABILITY OF MATERIALS

Our 2025 Annual Report, including the financial statements and financial statement schedules, has been filed with the SEC and provides additional information about us, which is incorporated by reference herein. It is available on the internet at www.sagimet.com and is available in paper form (other than exhibits thereto) by first class mail or other equally prompt means to beneficial owners of our Series A common stock, without charge, upon written request to: Chief Legal & Administrative Officer, Sagimet Biosciences Inc., 155 Bovet Road, Suite 303, San Mateo, California 94402. In addition, it is available to beneficial and record holders of our Series A common stock at www.astproxyportal.com/ast/27458.

PROXY VOTING INSTRUCTIONS Please detach along perforated line and mail in the envelope provided IF you are not voting via telephone or the Internet. 20430000000000001000 7 061226 COMPANY NUMBER ACCOUNT NUMBER ANNUAL MEETING OF STOCKHOLDERS OF SAGIMET BIOSCIENCES INC. June 12, 2026 NOTICE OF INTERNET AVAILABILITY OF PROXY MATERIALS: The Notice of Meeting, Annual Report on Form 10-K, proxy statement and proxy card are available at www.astproxyportal.com/ast/27458 INTERNET - Access www.voteproxy.com and follow the on-screen instructions or scan the QR code with your smartphone. Have your proxy card available when you access the web page. TELEPHONE - Call toll-free 1-800-PROXIES (1-800-776-9437) in the United States or +1-201-299-4446 worldwide from any touch-tone telephone and follow the instructions. Have your proxy card available when you call. Vote online/phone until 11:59 p.m. Eastern Time the day before the meeting. MAIL - Sign, date and mail your proxy card in the envelope provided as soon as possible. GO GREEN - e-Consent makes it easy to go paperless. With e-Consent, you can quickly access your proxy materials, statements and other eligible documents online, while reducing costs, clutter and paper waste. Enroll today via equiniti.com/us/ast-access to enjoy online access. Signature of Stockholder Date: Signature of Stockholder Date: Note: Please sign exactly as your name or names appear on this Proxy. When shares are held jointly, each holder should sign. When signing as executor, administrator, attorney, trustee or guardian, please give full title as such. If the signer is a corporation, please sign full corporate name by duly authorized officer, giving full title as such. If signer is a partnership, please sign in partnership name by authorized person. To change the address on your account, please check the box at right and indicate your new address in the address space above. Please note that changes to the registered name(s) on the account may not be submitted via this method. INSTRUCTIONS: To withhold authority to vote for any individual nominee(s), mark “FOR ALL EXCEPT” and fill in the circle next to each nominee you wish to withhold, as shown here: THE BOARD OF DIRECTORS RECOMMENDS A VOTE "FOR ALL NOMINEES" IN THE ELECTION OF CLASS III DIRECTORS AND "FOR" PROPOSAL 2. PLEASE SIGN, DATE AND RETURN PROMPTLY IN THE ENCLOSED ENVELOPE. PLEASE MARK YOUR VOTE IN BLUE OR BLACK INK AS SHOWN HERE x 1. The election of Class III directors for a three year term expiring in 2029: O Jennifer Jarrett O Anne Phillips, M.D. O David Happel O George Kemble, Ph.D. 2. The ratification of the appointment of Deloitte & Touche LLP as the independent registered public accounting firm for the fiscal year ending December 31, 2026. In their discretion, the proxies are authorized to vote upon such other business as may properly come before the Annual Meeting. This proxy when properly executed will be voted as directed herein by the undersigned shareholder. If no direction is made, this proxy will be voted FOR ALL NOMINEES in Proposal 1 and FOR Proposal 2. FOR FOR ALL NOMINEES WITHHOLD AUTHORITY FOR ALL NOMINEES FOR ALL EXCEPT (See instructions below) NOMINEES: MARK “X” HERE IF YOU PLAN TO ATTEND THE MEETING. AGAINST ABSTAIN

0------------------ . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ----------------14475SAGIMET BIOSCIENCES INC.155 Bovet Road, Suite 303San Mateo, California 94402THIS PROXY IS SOLICITED ON BEHALF OF THE BOARD OF DIRECTORSThe undersigned stockholder hereby appoints David Happel and Elizabeth Rozek asproxies, each with full power of substitution, to represent and vote as designated on thereverse side of this ballot, all the shares of Series A Common Stock of Sagimet BiosciencesInc. held of record and entitled to vote by the undersigned as of April 17, 2026, at the AnnualMeeting of Stockholders to be held on Friday, June 12, 2026, at 9:30 a.m. Pacific Time, orat any adjournment or postponement thereof, as well as to vote upon such other businessas may properly come before the Annual Meeting of Stockholders.(Continued and to be signed on the reverse side)1.1