MGF (Mechano Growth Factor) vs Follistatin 315
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
MGF (Mechano Growth Factor)Anabolic & IGF
Follistatin 315- Summary
- MGF (Mechano Growth Factor) is a splice variant of IGF-1 that is locally produced in muscle tissue in response to mechanical damage from exercise. It activates muscle satellite cells (stem cells) to proliferate and repair damaged fibers, making it specifically targeted at exercise-induced hypertrophy.
- Follistatin 315 is a splice variant isoform of follistatin produced by alternative mRNA processing. Unlike Follistatin 344 which is tethered to cell surfaces via heparan sulfate proteoglycans, FST-315 circulates freely in the bloodstream and has broader systemic distribution. It is the predominant circulating form and exerts systemic myostatin inhibition as well as FSH suppression, making it relevant to both muscle growth and reproductive endocrinology.
- Half-Life
- Native MGF: minutes. PEG-MGF: ~3 days
- ~3–5 hours (longer systemic circulation vs FST-344)
- Admin Route
- SubQ, IM
- SubQ, IM
- Research
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- Typical Dose
- 200–400 mcg
- No established human dosing protocol
- Frequency
- 1–2 times per week
- Research use only
- Key Benefits
- Activates muscle satellite cells for repair and growth
- Accelerates recovery from muscle damage
- Synergistic with IGF-1 LR3 (different mechanisms)
- Promotes muscle hypertrophy specifically at exercised muscles
- Faster recovery between training sessions
- Potential for injury repair in connective tissue
- Systemic myostatin inhibition for whole-body muscle growth
- Freely circulating — broader tissue distribution than FST-344
- Strong FSH-suppressive activity useful in certain hormonal protocols
- Potential for greater anabolic effect across multiple muscle groups simultaneously
- May be more relevant to reproductive endocrinology applications
- Studied in gene therapy approaches for muscular dystrophy
- Side Effects
- Muscle soreness (satellite cell activation)
- Injection site irritation
- Hypoglycemia risk (modest, less than IGF-1 LR3)
- Systemic FSH suppression — significant concern for fertility
- Greater potential for off-target effects vs FST-344 due to systemic distribution
- Limited human safety data
- Potential cardiac hypertrophy with prolonged high-dose exposure
- Stacks With
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