The myostatin-binding follistatin isoform behind muscle-growth research interest.
Also known as: FS-344 · FST-344 · follistatin precursor
Part of the Growth hormone & IGF peptides cluster
Overview
Follistatin-344 (FS-344) is the 344-amino-acid precursor isoform of follistatin, an activin-binding protein encoded by the FST gene. It antagonizes TGF-β superfamily ligands such as myostatin and activin, making it a focus of muscle-biology research. It is not an approved therapeutic in Canada.
Source & context
Biological / chemical source: Encoded by the human FST gene (344-residue precursor isoform)
Primary research or clinical context: Research protein studied in muscle biology; not an approved drug in Canada
Follistatin biology
Follistatin is an activin-binding glycoprotein that neutralizes several TGF-β superfamily ligands, most notably myostatin (GDF-8), a negative regulator of muscle mass. The FST gene is alternatively spliced; the 344-residue precursor (FS-344) is processed after signal-peptide removal into shorter circulating isoforms such as FS-315.
Why it draws search interest
Because myostatin restrains muscle growth, follistatin's ability to bind myostatin drives strong interest in muscle and performance contexts. Much of the compelling data comes from animal models and early gene-therapy studies rather than large human trials, so claims should be read cautiously.
Peptide vs protein note
Follistatin-344 is a full protein, not a short synthetic peptide, which affects how it is produced, delivered, and studied. Research programs have explored gene-therapy delivery of FS-344 rather than simple injection. This page is educational and offers no dosing or treatment advice.
FAQ about Follistatin-344
What is Follistatin-344?+
Follistatin-344 (FS-344) is the 344-amino-acid precursor isoform of follistatin, an activin-binding protein encoded by the FST gene. It antagonizes TGF-β superfamily ligands such as myostatin and activin, making it a focus of muscle-biology research. It is not an approved therapeutic in Canada.
Is Follistatin-344 an approved medicine?+
Follistatin-344 is discussed here as a research / educational topic. Research protein studied in muscle biology; not an approved drug in Canada. This is not medical advice.
What is the typical length of Follistatin-344?+
Follistatin-344 is commonly described as approximately 344 amino acids (Glycoprotein / activin-binding protein isoform).