Follistatin 315 vs AICAR
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Anti-Aging & LongevityFat Loss & Metabolic
AICAR- Summary
- 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.
- AICAR is a cell-permeable AMP analog that activates AMPK (AMP-activated protein kinase) — the master metabolic switch that triggers fat burning, mitochondrial biogenesis, and adaptations normally only achieved through exercise. It has been called the 'exercise in a pill' compound.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~2–3 hours
- Admin Route
- SubQ, IM
- SubQ, IV
- Research
- —
- —
- Typical Dose
- No established human dosing protocol
- 25–50 mg
- Frequency
- Research use only
- 3–5 times per week
- Key Benefits
- 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
- AMPK activation mimics aerobic exercise adaptations
- Increased fat oxidation and endurance
- Mitochondrial biogenesis (PGC-1alpha)
- Improved insulin sensitivity and glucose metabolism
- Anti-inflammatory effects
- Potential cardiac protection during ischemia
- Synergistic with actual exercise training
- Reduces hepatic glucose production
- Side Effects
- 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
- Hypoglycemia risk
- Lactic acidosis at high doses (animal data)
- Injection site irritation
- Stacks With
- —
- —