Follistatin 315 vs Larazotide Acetate
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Recovery & Repair
Larazotide Acetate- 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.
- Larazotide acetate is an 8-amino acid peptide (Gly-Gly-Val-Leu-Val-Gln-Pro-Gly) derived from Zonula Occludens Toxin (ZOT) of Vibrio cholerae. It paradoxically acts as a ZOT antagonist to close tight junctions and reduce intestinal permeability ('leaky gut'). It is the most advanced clinical compound targeting gut permeability directly.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Local gut action; minimal systemic exposure
- Admin Route
- SubQ, IM
- Oral
- Research
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- Typical Dose
- No established human dosing protocol
- 0.5-2 mg
- Frequency
- Research use only
- 3x 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
- Directly reduces intestinal tight junction permeability
- Clinical efficacy in celiac disease (Phase 3 trials)
- Reduces systemic inflammation from gut permeability
- Targets root cause of leaky gut (Zonulin pathway)
- Local gut action without systemic absorption
- Potential application in IBS, IBD, autoimmune conditions
- 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 (mild, dose-dependent)
- Nausea (rare)
- Well-tolerated overall in clinical trials
- Stacks With
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