FS-344 · activin/myostatin-binding glycoprotein
Follistatin-344
High-caution Anabolic research
What it is
Follistatin isoforms bind activin and myostatin and can drive large muscle-mass changes in animals and experimental gene therapy. Lyophilized FS-344 vials on peptide sites are not those medical products.
Benefits in plain language
What researchers and reference users usually mean when they talk about this compound. These are study themes and common claims — not a promise that it will do this in you.
- Follistatin binds myostatin, the brake that stops muscles from growing without limit.
- The fantasy is rapid muscle gain by lifting that brake. Gene-therapy and research-peptide versions are not the same thing.
- This is one of the more serious “don’t treat it like a pre-workout” compounds.
- Unknowns around other tissues that also use myostatin/activin signaling.
If a branded, FDA-approved product exists, that label is the only dose that is actually authorized. Research-chemical vials are a different object.
Mechanism of action
Neutralizing myostatin/activin TGF-β signals removes a brake on skeletal-muscle growth. Off-target activin biology (reproduction, inflammation) still matters.
Possible side effects / caveats
Unpredictable anabolic and endocrine effects, product-identity risk, and no clean human injectable protocol from peptide vials.
Protocol ranges
| Source tier | Amount | Frequency / duration | Notes |
|---|---|---|---|
| Research culture | mg-range talk appears | Cycled in forums | Not endorsed here as a dose |
| Reality check | Identity first | COA + what was actually synthesized | Many vials will not match the name |