fol-ih-STAT-in
A protein that blocks myostatin — the molecule that limits muscle growth — potentially allowing greater muscle development.
Also known as: FST, Follistatin 344
Last reviewed: April 2026
Your body produces myostatin to limit muscle growth. Follistatin binds to and neutralizes myostatin, removing this natural brake on muscle development. In animal studies, follistatin overexpression leads to dramatic muscle hypertrophy.
Injection
Frequency
Daily for short cycles
Pain Level
●○○ Minimal
Self-Administered
Yes — at home
Typical Range
100mcg – 200mcg
Month 1–2
Potential strength improvements alongside training.
Month 3+
Possible body composition changes. Very variable.
Overall: Mild
Limited data
Human side effect profile not well characterized.
• Pregnancy
• Very limited human data
• Cardiovascular disease (theoretical concern with uncontrolled muscle growth)
• Insufficient data
Pregnancy: Not studied. Avoid.
Follistatin targets muscle growth specifically via myostatin. TB-500 targets tissue repair broadly. Different goals despite both being in the 'muscle' category.
Open Full Comparison Tool →This compound is in early research stages. We do not currently offer it.
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This compound is in early research stages. It has not been FDA-approved and may not be available through compounding pharmacies. The information below is for educational purposes only. Do not attempt to self-administer research compounds.