Follistatin
Follistatin-288
Overview
Follistatin is a naturally occurring glycoprotein that functions as a potent inhibitor of myostatin and activin — two members of the TGF-beta superfamily that suppress muscle growth. By neutralizing myostatin follistatin removes the brakes on muscle development enabling dramatically enhanced muscle hypertrophy. Animals with follistatin overexpression develop extraordinary muscle mass — the famous Belgian Blue cattle with myostatin mutations display a similar phenotype. Follistatin has attracted intense interest in the muscle research community for applications in muscle wasting diseases sarcopenia and performance enhancement.
Mechanism of Action
Follistatin is a high-affinity binding protein that sequesters myostatin activins and BMPs preventing them from binding to their receptors. Myostatin (GDF-8) normally acts on muscle satellite cells and myofibers to inhibit protein synthesis limit satellite cell activation and suppress muscle growth — it evolved as a mechanism to prevent excessive muscle mass. By binding and neutralizing myostatin follistatin removes this inhibitory signal allowing unrestricted activation of the PI3K/Akt/mTOR anabolic signaling pathway in muscle tissue. Follistatin also affects reproductive function bone metabolism and other tissues where activins play regulatory roles. Gene therapy approaches delivering follistatin to muscle tissue have shown dramatic results in muscular dystrophy models and are entering clinical trials. The injectable research peptide FS-344 is a truncated follistatin fragment designed to retain myostatin-inhibiting activity.
Where does Follistatin sit?
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Dosage Information
Typical Dose
100 mcg daily (research protocols for FS-344 fragment)
Frequency
Once daily
Administration
Subcutaneous injection
Notes
Full-length follistatin has very limited availability. FS-344 (follistatin 344) fragment is the form used in research contexts. Gene therapy approaches using AAV-follistatin are in clinical trials for muscular dystrophy. Extreme caution — limited human safety data for injectable forms.
Potential Side Effects
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Quick Facts
- Administration
- Subcutaneous injection
- Typical Dose
- 100 mcg daily (research protocols for FS-344 fragment)
- Frequency
- Once daily
- References
- 0 curated + 35 from PubMed
- Evidence Score
- 28.3 / 100