Follistatin 315 vs Syn-Coll
Side-by-side comparison of key properties, dosing, and research.
Anabolic & IGF
Follistatin 315Skin & CosmeticAnti-Aging & Longevity
Syn-Coll- 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.
- Syn-Coll is a palmitoylated tripeptide (Palmitoyl Tripeptide-5) that mimics thrombospondin-1 to activate TGF-beta, the primary growth factor driving collagen synthesis in the dermis. It is one of the most mechanistically direct collagen-stimulating peptides in cosmetic formulations.
- Half-Life
- ~3–5 hours (longer systemic circulation vs FST-344)
- Extended (lipid depot in stratum corneum)
- Admin Route
- SubQ, IM
- Topical
- Research
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- Typical Dose
- No established human dosing protocol
- 0.005-0.05% in formulation
- 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
- Directly activates TGF-beta for potent collagen synthesis stimulation
- Increases dermal thickness and firmness
- Reduces depth of wrinkles and fine lines
- Improves skin elasticity
- Clinically validated in collagen induction studies
- Complementary to retinoids or vitamin C
- 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
- Generally well-tolerated
- Rare mild irritation at high concentrations
- Possible sensitivity in individuals with inflammatory skin conditions
- Stacks With
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