Category: peptide
Aliases: FS-344, FST-344
Native secreted protein that binds and inhibits myostatin, activin A, and related TGF-β family ligands. Two splice isoforms: FS-344 (longer) and FS-288 (shorter; higher cell-surface heparan-sulfate binding affinity). FS-344 is what's commonly offered in research-grade peptide markets; note the large protein (37 kDa) is NOT a true peptide and most vendor product purity claims are unreliable.