▶ FOLLISTATIN-344 · SUBTOPIC · MECHANISM
FOLLISTATIN-344 Mechanism
For Laboratory Research Use Only. The mechanistic information below is descriptive of published research. No human dose is recommended. No clinical claim is made.
MECHANISM OF ACTION
344-amino-acid isoform of follistatin, the endogenous antagonist of myostatin (GDF-8) and activin. Binds and neutralizes myostatin to release the brake on skeletal muscle growth. Animal models report substantial lean-mass gains. WADA-prohibited under Section S2.
PHARMACOKINETIC HALF-LIFE
Reported half-life for FOLLISTATIN-344: Several days (long-acting in animal models). Half-life determines the kinetic window across which receptor occupancy is maintained and frames the dosing rhythm used in published literature.
PRIMARY SEQUENCE
FOLLISTATIN-344 is a defined sequence: 344-residue isoform of the FST gene · contains FSD1-FSD3 follistatin domains (full sequence reproduces UniProt P19883 isoform 2). Synthesis proceeds via solid-phase peptide synthesis with HPLC-verified identity confirmation.
MECHANISM CATEGORIES
FOLLISTATIN-344 is tagged in 2 mechanism categories on PEPPUDEX. Each category aggregates the broader pharmacology of related compounds.
The myostatin axis is the dominant negative regulator of skeletal muscle mass. Myostatin (GDF-8), a TGF-beta family member, signals through ActRIIB on skeletal muscle to inhibit hypertrophy. Follistatin-344 binds and neutralizes myostatin and activin, releasing the brake on muscle growth in animal models. Antagonism of this axis is the basis for several investigational pharmaceutical programs in muscle-wasting disease.
The growth hormone axis is regulated by two complementary upstream signals: GHRH (stimulatory, from the hypothalamus, acting on the GHRH receptor on pituitary somatotrophs) and ghrelin (stimulatory, from the stomach, acting on the GHS-R1a). Research peptides target both arms: GH-axis reference and CJC-1295 (GHRH analogs); ipamorelin, GHRP-6, and hexarelin (ghrelin-receptor agonists).
MECHANISTIC OUTCOMES IN LITERATURE
The following outcomes are the mechanistic endpoints reported in the peer-reviewed literature, with PEPPUDEX evidence grades. Grades reflect study quality and replication, not clinical recommendation.
Well-characterized binding to myostatin and activin. Lee et al. multi-paper evidence base for follistatin antagonism of TGF-beta family ligands.
Kota 2009 (PMID 20371475) follistatin gene therapy in primate model produced substantial muscle pathology improvement in Duchenne muscular dystrophy.
No completed long-term human Phase 3 trials for body-composition endpoints.
MECHANISM Q+A
▶ How does follistatin work?
Follistatin binds myostatin (GDF-8) and activin in a 2:1 ratio, sequestering them away from their cognate ActRIIB receptor on skeletal muscle. The receptor blockade releases the negative regulation that myostatin normally imposes on muscle hypertrophy, increasing lean mass in animal models.
CITED LITERATURE
- Lee SJ, Lee YS, Zimmers TA, et al.. Regulation of muscle mass by follistatin and activins. Mol Endocrinol 2010. PMID 20801891. link
- Kota J, Handy CR, Haidet AM, et al.. Follistatin gene delivery enhances muscle growth and strength in nonhuman primates. Sci Transl Med 2009. PMID 20371475. link
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▶ LAST UPDATED · 2026-05-25