X0508 4 2025-03-06 0001658551 Amylyx Pharmaceuticals, Inc. AMLX 0001898644 Cohen Joshua B C/O AMYLYX PHARMACEUTICALS, INC. 43 THORNDIKE STREET CAMBRIDGE MA 02141 true true false false Co-Chief Executive Officer false Common Stock 2025-03-06 4 A false 180118 0 A 3376770 D Stock Option (Right to Buy) 3.61 2025-03-06 4 A false 270177 0 A 2035-03-05 Common Stock 270177 270177 D The reported transaction involves the Reporting Person's receipt of a restricted stock unit ("RSU") award. The RSUs shall vest in 4 equal annual installments, with the first installment vesting on March 1, 2026, subject to the Reporting Person's continued service to the Issuer through each such vesting date. 25% of the shares subject to the option shall vest and become exercisable on March 1, 2026, and the remaining shares shall vest monthly over the remaining 36 months, subject to the Reporting Person's continuous service to the Issuer through each such vesting date. /s/ Joshua B. Cohen 2025-03-10