Follistatin-344 Unlock Your Muscle Growth Potential. FST-344 is a research peptide that functions as a myostatin inhibitor, supporting the body’s natural ability to develop lean muscle tissue. By modulating myostatin and activin signaling, FST-344 is being investigated for its potential to promote muscle hypertrophy, strength, recovery, and tissue regeneration. It has gained significant interest in performance optimization and muscle-wasting research due to its unique mechanism of action.