Larimar Therapeutics Inc

Our 2024 Annual Report, including the consolidated financial statements, has been filed with the SEC and provides additional information about us, which is incorporated by reference herein. It is available on the Internet atwww.larimartx.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 common stock, without charge, upon written request to Chief Financial Officer, Larimar Therapeutics, Inc., Three Bala Plaza East, Suite 506, Bala Cynwyd, PA 19004 or at (844) 511-9056. In addition, it is available to beneficial holders of our common stock athttp://www.edocumentview.com/LRMR and to record holders of our common stock athttp://www.envisionreports.com/LRMR.

Using a black ink pen, mark your votes with an X as shown in this example. Please do not write outside the designated areas. Your vote matters – here’s how to vote! You may vote online or by phone instead of mailing this card. Online Go to www.envisionreports.com/LRMR or scan the QR code — login details are located in the shaded bar below. Phone Call toll free 1-800-652-VOTE (8683) within the USA, US territories and Canada Save paper, time and money! Sign up for electronic delivery at www.envisionreports.com/LRMR 2025 Annual Meeting Proxy Card • IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.• 1. Election of Class II Director for a Three-Year Term Expiring in 2028 01 -Thomas E. Hamilton For Withhold 2. Approval, on an Advisory Basis, of the Compensation of our Named Executive Officers in 2024 For Against Abstain 3. Ratification of Appointment of PricewaterhouseCoopers LLP as our Independent Registered Public Accounting Firm for the 2025 Fiscal Year Please sign exactly as name(s) appears hereon. Joint owners should each sign. When signing as attorney, executor, administrator, corporate officer, trustee, guardian, or custodian, please give full title. Date (mm/dd/yyyy) — Please print date below. Signature 1 — Please keep signature within the box. Signature 2 — Please keep signature within the box. 1UPX 044KLD

The 2025 Annual Meeting of Stockholders of Larimar Therapeutics, Inc. will be held on Tuesday, May 13, 2025, at 10:00 A.M. Eastern time, virtually via live webcast at meetnow.global/ML6NWDL. To access the virtual meeting, you must have the information that is printed in the shaded bar located on the reverse side of this form. Important notice regarding the Internet availability of proxy materials for the Annual Meeting of Stockholders. The material is available at: www.envisionreports.com/LRMR Small steps make an impact. Help the environment by consenting to receive electronic delivery, sign up at www.envisionreports.com/LRMR • IF VOTING BY MAIL, SIGN, DETACH AND RETURN THE BOTTOM PORTION IN THE ENCLOSED ENVELOPE.• Larimar Therapeutics, Inc. Notice of 2025 Annual Meeting of Stockholders Proxy Solicited by Board of Directors for Annual Meeting — May 13, 2025 Carole S. Ben-Maimon, M.D.; Michael Celano or either of them, each with the power of substitution, are hereby authorized to represent and vote the shares of the undersigned, with all the powers which the undersigned would possess if personally present, at the Annual Meeting of Stockholders of Larimar Therapeutics, Inc. to be held on May 13, 2025 or at any postponement or adjournment thereof. Shares represented by this proxy will be voted as instructed by the undersigned. If no such directions are indicated, the Proxies will have authority to vote FOR the nominee listed and FOR Proposals 2 and 3. In their discretion, the Proxies are authorized to vote upon such other business as may properly come before the meeting. (Items to be voted appear on reverse side) Change of Address — Please print new address below. Comments — Please print your comments below.