FS-344

Follistatin 344 (FS-344) is a 344-amino acid isoform of the endogenous glycoprotein follistatin with a molecular weight of approximately 37 kDa, characterized by its high-affinity binding and neutralization of activin, myostatin (GDF-8), and other members of the TGF-β superfamily — acting as a potent endogenous antagonist of these ligands by forming non-signaling complexes that prevent receptor binding and downstream SMAD2/3 signaling pathway activation in target tissues.

The FS-344 isoform is distinguished by its heparin-binding domain, which mediates cell surface and extracellular matrix association in target tissues — with research demonstrating that this tissue-binding profile concentrates its antagonist activity locally at sites of expression, making it a particularly useful research tool for investigating tissue-specific roles of activin and myostatin signaling in skeletal muscle biology, reproductive axis regulation, and bone metabolism in preclinical models.

Research has focused on Follistatin 344’s role as a myostatin and activin antagonist in skeletal muscle hypertrophy models, its regulatory function in the hypothalamic-pituitary-gonadal axis through FSH suppression, and its broader role in TGF-β superfamily signaling biology — with its mechanism complementing anabolic research tools such as IGF-1 LR3 and body composition research compounds such as MOTS-C for comprehensive muscle and metabolic biology research. For further reading see: Follistatin myostatin antagonism and muscle biology research (PubMed).

Specifications:

• Purity: ≥99% (HPLC verified)
• Form: Lyophilized powder
• Storage: −20°C

For Research Use Only.