Follistatin 344
UnregulatedAlso known as: FST-344, Follistatin
Growth & AnabolicLast reviewed: April 28, 2026
A naturally occurring glycoprotein that acts as a potent inhibitor of myostatin — the protein that limits muscle growth. Follistatin 344 is the most common isoform used in research contexts. Inhibiting myostatin theoretically removes the body's natural brake on muscle development.
Mechanism of Action
Binds to and neutralizes myostatin (GDF-8) and activin, preventing them from signaling through the ActRIIB receptor. This removes the inhibitory signal on muscle satellite cells, allowing greater muscle fiber growth and regeneration. Also affects bone density and fat metabolism through activin pathway modulation.
Common Uses
- Muscle mass enhancement
- Strength improvement
- Muscular dystrophy research
- Recovery from muscle-wasting conditions
Known Risks
- Very limited human clinical data
- Potential for uncontrolled muscle growth
- Tendon and connective tissue may not keep pace with muscle growth
- Cardiovascular effects of myostatin inhibition not fully characterized
- Long-term safety completely unknown
- High potential for misuse in athletic contexts
Regulatory Status
Not FDA-approved and not on any compounding list. Available as a research chemical. Myostatin inhibition is an active area of pharmaceutical research for muscular dystrophy — several drug candidates are in clinical trials, but follistatin itself has not advanced to approved drug status.
Common Protocols
Protocol information is for educational reference only. Dosing varies significantly by individual, condition, and physician guidance. Always work with a licensed healthcare provider.
Subcutaneous or intramuscular injection
Typical Dose
50–100 mcg
Frequency
Once daily
Cycle Length
10–30 days (short cycles due to limited safety data)
Very limited human dosing data — protocols are largely community-derived. Inject near target muscle groups. Monitor for unusual muscle soreness or joint stress — muscle may grow faster than connective tissue can adapt.
Related Compounds
Research References
This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy. Data is compiled from published research and regulatory sources and may not reflect the most recent developments.