Follistatin

Key Benefits#

• Potent myostatin inhibition enabling supraphysiological muscle growth
• Increases skeletal muscle mass and fiber size
• May accelerate recovery from muscle injury
• Potential benefits in muscular dystrophy and sarcopenia
• Synergistic with IGF-1 and growth hormone in anabolic protocols
• Animal studies show dramatic increases in muscle mass
• Reduces muscle fibrosis in dystrophic models

Mechanism of Action#

Follistatin binds myostatin (GDF-8) and activin A with high affinity, preventing them from signaling through their receptors (ActRIIB). Myostatin is a member of the TGF-beta superfamily and its primary role is to limit skeletal muscle mass. By neutralizing myostatin, follistatin removes inhibition of the PI3K/Akt/mTOR pathway, allowing anabolic signaling to proceed uninhibited. Follistatin also inhibits FSH secretion via activin antagonism, with implications for reproductive physiology.

Dosing Protocols#

Side Effects#

• Potential for excessive muscle growth if doses are not controlled
• FSH suppression with implications for fertility in women
• Theoretical risk of cardiac hypertrophy with prolonged high-dose use
• Limited human safety data available
• Joint stress from rapid muscle mass increases

Contraindications#

Not FDA approved. Extreme caution required. Limited human trial data. Contraindicated in pregnancy. Not appropriate for individuals with pre-existing cardiac conditions without medical oversight.

Storage#

Lyophilized powder: store at -20°C. Reconstituted: refrigerate at 2–8°C, use within 3–5 days.

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