Follistatin 315 vs Exenatide
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315GLP-1 / Weight Loss AgonistsCognitive Enhancement
Exenatide- 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.
- Exenatide is a GLP-1 receptor agonist derived from the Gila monster lizard peptide exendin-4, with 53% homology to human GLP-1 and natural resistance to DPP-4 degradation. Available as twice-daily (Byetta) or once-weekly (Bydureon) formulation, it is also being studied for Parkinson's disease neuroprotection.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~2.4 hours (Byetta/twice-daily); Bydureon BCISE: weekly via microsphere release
- Admin Route
- SubQ, IM
- SubQ
- Research
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- Typical Dose
- No established human dosing protocol
- 5 mcg, titrate to 10 mcg
- Frequency
- Research use only
- Twice 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
- Blood glucose control in type 2 diabetes
- Weight loss (average 2–3 kg in clinical trials)
- Once-weekly extended-release formulation available
- Reduces appetite and food intake
- Possible neuroprotective in Parkinson's disease (Phase II trials)
- Reduces systemic inflammation
- May protect pancreatic beta cells
- Cardiovascular neutral or potentially protective
- 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
- Nausea (most common, especially initially)
- Vomiting
- Diarrhea
- Headache
- +4 more
- Stacks With
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