Page data last changed: . Registry refreshes and identity assessments are separate from scientific content review.
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.
Structure & chemistry
Molecular identity & reference confidence
Reference mass unavailable
Reference values are taken from the cited molecular record or curated profile. A database match is not independent laboratory verification; modifications, counter-ions, and formulations can change the measured mass.
- Molecular form
- Follistatin-344 (source record; form not independently established)
- Species
- Not established by this molecular identity audit
- Termini (N / C)
- Not specified / Not specified
Average reference mass
Reference policy updated: 2026-10-05
Clinical development snapshot
ClinicalTrials.gov lists 1 registered study with “Follistatin-344” as an intervention (snapshot 2026-09-06). A registry footprint is not evidence of efficacy or approval.
| NCT | Title | Phase | Status | Updated |
|---|---|---|---|---|
| NCT06411366 | Phase I: Safety and Efficacy of an Injectable Follistatin Plasmid Gene Therapy in Humans | Phase 1 | completed | 2024-05-13 |
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.
What Canadian product status is recorded for Follistatin-344?+
Canadian product status for Follistatin-344 has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.
What is the typical length of Follistatin-344?+
Follistatin-344 is commonly described as approximately 344 amino acids (Glycoprotein / activin-binding protein isoform).