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Last reviewed: March 2026Sources: PubMed, FDA, WADA Prohibited List

Evidence graded using the PeptideScholar A-D system

Follistatin-344

DLimited Data
30
Low Credibility
1 cited studyy · Evidence level D

Follistatin isoform (autocrine/secreted glycoprotein) · 344 amino acids

Not FDA ApprovedWADA Banned

Follistatin-344 is the full-length human follistatin isoform that binds and inhibits myostatin, activin, and other TGF-beta family members. It is a naturally occurring protein, not a synthetic peptide, but the recombinant form is sold as a research chemical for muscle growth. Gene therapy trials using follistatin have been conducted for muscular dystrophy.

Mechanism of Action

Binds to myostatin and activin with high affinity, preventing them from activating ActRIIB receptors on muscle cells. Myostatin normally limits muscle growth; blocking it removes this brake, allowing muscle hypertrophy and hyperplasia. Also has roles in reproductive biology and inflammation via activin inhibition.

Benefits

  • Potent muscle hypertrophy in animal models via myostatin inhibition
  • Investigated in gene therapy trials for muscular dystrophy
  • May improve muscle function in degenerative muscle diseases
Not Medical Advice — Research-Reported Information Only

This content is for informational purposes only and does not constitute medical advice.

Follistatin-344 — Dosing in Published Research

Reported Routes: Subcutaneous injection, Intramuscular injection
No established human dosing for the recombinant protein. Gene therapy trials used localized intramuscular AAV delivery. Research chemical dosing is entirely unvalidated and varies by supplier.

The dosing information above is sourced from published research literature and clinical trials. These are not recommendations. Individual responses vary. Always consult a healthcare provider before considering any peptide-based therapy.

Side Effects

  • No human safety data for exogenous follistatin-344 protein
  • Reproductive effects (follistatin regulates FSH via activin inhibition)
  • Ocular side effects reported in gene therapy trials (retinal detachment)
  • Immunogenicity risk with repeated injections of foreign protein
  • Not approved for human use as a protein drug

Considering Peptide Research?

Follistatin-344 is not FDA-approved. Always consult a licensed healthcare provider before considering any peptide.

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Research & Evidence

ReviewDrug Test Anal, 2020

Detection of black market follistatin 344.

Confirmed the presence of follistatin-344 in black market products sold online, highlighting unregulated distribution and quality concerns

PMID: 33460286

References

  1. 1. Detection of black market follistatin 344.. Drug Test Anal, 2020. “Confirmed the presence of follistatin-344 in black market products sold online, highlighting unregulated distribution and quality concerns” [PMID: 33460286]

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Follistatin-344 FAQ

Medical Disclaimer

This content is for informational and educational purposes only and does not constitute medical advice, diagnosis, or treatment recommendations.

Always consult a qualified healthcare provider before starting, stopping, or modifying any treatment. Do not disregard professional medical advice based on information found on this site.

No claims of therapeutic efficacy are made for substances that are not FDA-approved for the discussed indications. Research citations reflect published findings and do not imply endorsement.

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