LL-37 vs Follistatin 315
Side-by-side comparison of key properties, dosing, and research.
Immune SupportRecovery & Repair
LL-37Anabolic & IGF
Follistatin 315- Summary
- LL-37 is the only known human cathelicidin antimicrobial peptide. It kills bacteria, fungi, and viruses by disrupting their membranes, while simultaneously modulating immune responses. Used for antimicrobial protection, immune priming, and wound healing.
- 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.
- Half-Life
- Very short (~1–2 hours) in plasma due to protease degradation; topical use bypasses systemic clearance
- ~3–5 hours (longer systemic circulation vs FST-344)
- Admin Route
- SubQ, Topical, Intranasal
- SubQ, IM
- Research
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- Typical Dose
- 100–300 mcg
- No established human dosing protocol
- Frequency
- 2–3x per week
- Research use only
- Key Benefits
- Broad-spectrum antimicrobial (bacteria, fungi, viruses)
- Promotes wound healing and angiogenesis
- Immune system modulation — enhances innate immunity
- Reduces LPS-mediated endotoxemia
- Anti-biofilm activity against resistant organisms
- Promotes tissue regeneration and keratinocyte migration
- May protect against sepsis
- 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
- Side Effects
- Injection site redness and irritation
- Mild inflammatory response at injection site
- Potential pro-inflammatory at high doses
- Rare: fever or flu-like symptoms at initiation
- 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
- Stacks With
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