Follistatin 315 vs Matrixyl
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Skin & Cosmetic
Matrixyl- 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.
- Matrixyl is the most widely used collagen-stimulating cosmetic peptide. As a matrikine — a fragment of type I procollagen — it signals skin cells to synthesize new collagen, elastin, and fibronectin, reducing wrinkle depth and improving skin firmness and elasticity.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- N/A — topical; sustained signaling effects on fibroblasts persist beyond single application
- Admin Route
- SubQ, IM
- Topical
- Research
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- Typical Dose
- No established human dosing protocol
- 3–8% concentration
- Frequency
- Research use only
- Once or 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
- Stimulates collagen I, III, and IV synthesis
- Increases fibronectin and glycosaminoglycan production
- Reduces wrinkle depth and length by 27–68% (studies)
- Improves skin firmness and elasticity
- Reduces dark circles and undereye bags
- Synergistic with retinol, vitamin C, and growth factors
- Suitable for all skin types including sensitive
- Well-studied with published clinical data
- 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
- Exceptional safety profile
- Non-irritating, suitable for sensitive skin
- No known adverse effects at cosmetic concentrations
- Stacks With
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