Follistatin 315 vs Alpha-GPC
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Cognitive Enhancement
Alpha-GPC- 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.
- Alpha-GPC is the most bioavailable form of choline, readily crossing the blood-brain barrier to rapidly increase acetylcholine levels. It enhances cognitive performance, supports GH secretion, and is used as an essential complement to many nootropic peptides (especially those that increase acetylcholine demand like Noopept and Dihexa).
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~4–6 hours
- Admin Route
- SubQ, IM
- Oral, SubQ
- Research
- —
- —
- Typical Dose
- No established human dosing protocol
- 300–600 mg
- Frequency
- Research use only
- 1–2x daily
- 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
- Rapidly raises brain acetylcholine levels
- Enhances memory formation and recall
- Prevents headaches from nootropic peptides (choline donor)
- Stimulates growth hormone secretion (modest)
- Improves attention and processing speed
- Neuroprotective in Alzheimer's and cognitive decline
- Approved in Europe for Alzheimer's therapy
- Enhances power output in athletes (pre-workout)
- 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
- Headache (paradoxically, from excess acetylcholine at very high doses)
- Nausea at doses > 1200 mg
- Dizziness
- Fatigue at high doses
- +1 more
- Stacks With
- —
- —