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Follistatin 344/315
Phase 2 TrialsAs of 2026, no injectable follistatin product is FDA-approved for any indication.
Follistatin 344/315
Description
A myostatin-binding protein that promotes muscle growth by inhibiting myostatin's limiting effects on muscle development.
Dose:50 mcg
Frequency:Training days (8 weeks on/off cycle)
Administration Method: IM
CategoryMyostatin Inhibitor
Half-LifeApproximately 2-3 days (follistatin protein).
Overview
Follistatin is a glycoprotein primarily produced in the liver and found in most body tissues. Different forms exist, including Follistatin 344 (FS-344) used in gene therapy, and Follistatin 315, the main circulating form that primarily targets muscle tissue.
Mechanism of Action
Follistatin blocks the action of activins, myostatin, GDF-11, and follicle-stimulating hormone (FSH). Its effects on muscle growth are primarily due to myostatin inhibition. Follistatin increases in muscle tissue in response to damage and promotes cell growth throughout the body.
Benefits
- •Muscle growth
- •Myostatin inhibition
- •Strength increase
- •Muscle mass
- •Athletic performance
Reported Side Effects
- •Injection site reactions
- •Muscle/joint pain
- •Theoretical effects on reproductive hormones
- •Limited human data