Follistatin 344
Muscle In trials Human trials
Also called FST-344, Activin-binding protein
A lab-made form of follistatin, a natural protein that binds and neutralizes myostatin and activin. Because those signals limit muscle growth, raising follistatin increased muscle mass in animal studies. It was also the basis of gene-therapy trials in muscular dystrophy.
Evidence at a glance
- Evidence
- Human trials — Studied in people
- Status
- Reached clinical trials
- Dosing
- No human study has set a dose
Human data used gene therapy, not the peptide itself. Blocking myostatin broadly also affects reproductive hormones.
What studies report
- Large gains in muscle mass in mice and monkeys
- Increased thigh muscle and walking distance in a small gene-therapy trial in Becker muscular dystrophy
How it works
Binds and neutralises myostatin and activin in circulation. Since those signals restrain muscle growth, removing them allows both fibre enlargement and, in animals, an increase in fibre number.
Where it acts
Skeletal muscleThe library groups this compound under Muscle. The diagram shows that target, not every tissue it reaches.
Illustrated
AI-generated subject illustration; not a depiction of the compound or evidence of its effects.
Why people take it
Reasons people seek it out — not a list of proven effects.
In practice Unapproved use
- A high-cost, short-run choice in competitive bodybuilding
Reported real-world use, not evidence and not a recommendation.
Dosing
No human study has established a dose for this compound.
What people report using Not evidence
- 100 mcg daily in short runs, at high cost
Human data used gene therapy, not the peptide. No established dosing.
Reported for reference, not as instruction. Nothing here is a recommendation to take anything, and most of these compounds are not approved for human use.
Status: Animal research; small gene-therapy trials in humans. Not approved.
- Route
- Subcutaneous injection, from reconstituted lyophilised powder
- Molecular weight
- ≈38 kDa
- Available as
- 1 mg
Search PubMed for Follistatin 344 → We link a live search rather than a fixed citation list, so it stays current and nothing here is a reference we have not checked.
Educational information only. Nothing here is medical advice, a dosing protocol, or a recommendation to use any compound. Most entries describe substances not approved for human use. Talk to a licensed clinician before acting on anything you read here. How to read these entries.