Follistatin 315 vs Teduglutide
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Recovery & Repair
Teduglutide- 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.
- Teduglutide is a GLP-2 (glucagon-like peptide-2) analog with enhanced stability. Unlike GLP-1, GLP-2 specifically acts on the intestinal epithelium to increase intestinal length, villus height, and absorption surface area. FDA-approved as Gattex for short bowel syndrome, it is also being investigated for IBD, leaky gut, and mucosal healing.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- ~2 hours; once-daily dosing due to gut-specific residence
- Admin Route
- SubQ, IM
- SubQ
- Research
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- Typical Dose
- No established human dosing protocol
- 0.05 mg/kg/day
- Frequency
- Research use only
- Once 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
- Increases intestinal villus height and absorption surface area
- Reduces intestinal permeability (leaky gut)
- FDA-approved for short bowel syndrome
- Reduces parenteral nutrition dependence in SBS patients
- Promotes intestinal mucosal healing in IBD
- Increases tight junction proteins ZO-1 and occludin
- 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
- Injection site reactions
- Abdominal pain and bloating
- Nausea
- Risk of intestinal polyp growth (requires colonoscopy surveillance)
- +1 more
- Stacks With
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