A 344-amino-acid glycoprotein that binds and neutralizes activin, myostatin (GDF-8), and other TGF-β superfamily ligands with high affinity. Follistatin-344 is the longest isoform, containing a heparin-binding domain that anchors it to cell surfaces — providing localized myostatin inhibition rather than systemic neutralization. By blocking myostatin signaling, follistatin-344 removes the primary endogenous brake on skeletal muscle growth. The follistatin-myostatin axis is the most validated genetic pathway for muscle mass regulation.
Research FocusMuscle hypertrophy, myostatin biology, TGF-β signaling, sarcopenia, muscular dystrophy
ReconstitutionBacteriostatic water — reconstitute gently, do not vortex
Stability7–14 days at 2–8°C; protein sensitive to denaturation
Key distinction: Natural myostatin antagonist — the heparin-binding domain of the 344 isoform provides localized rather than systemic myostatin neutralization, distinguishing it from the circulating FS-315 isoform.
Scientific Evidence
Published Research
[1]
Lee SJ, McPherron AC. Regulation of myostatin activity and muscle growth. Proc Natl Acad Sci USA 2001;98:9306-9311 — PubMed 11459935
[2]
Haidet AM et al. Long-term enhancement of skeletal muscle mass and strength by single gene administration of myostatin inhibitors. Proc Natl Acad Sci USA 2008;105:4318-4322 — PubMed 18334646
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