LL-37 FAQ: common questions answered

A human defense peptide with mixed topical wound-trial results and no established injection regimen.

Also called: LL37, Cathelicidin LL-37, hCAP18/LL-37.

Anti-inflammatory and antimicrobial peptides · Human cathelicidin antimicrobial and immune-signaling peptide.

  • Is LL-37 FDA-approved? No FDA-approved product or label. FDA warns of immune reactions, peptide impurities, reproductive harm and tissue-specific tumor effects.
  • How do people take it? Under the skin, once daily. Up to 6 weeks, as discussed. Source: reported by users, not an established dose.
  • What's the difference between LL-37 and Thymosin alpha-1? LL-37: a human defense peptide with mixed topical wound-trial results and no established injection regimen. Thymosin alpha-1: an immune-signaling peptide with overseas approvals and mixed trial results. Why people pair them: discussed with LL-37 for immune goals in a proposed autoimmune stack.
  • Can I take it with Thymosin alpha-1? Discussed with LL-37 for immune goals in a proposed autoimmune stack. No combination trial; effects on autoimmune disease may be unpredictable. Source: reported by users. Ask a doctor before combining anything.
  • Is it banned in sport? Yes. It is banned in and out of competition (WADA 2026). Inferred from S0 for unapproved pharmacological substances. Neither peptide is named individually; athletes should verify with their anti-doping body.
  • How long does a mixed vial last? No validated shelf life for community mixtures. The wound trial mixed its controlled formulation immediately before application.

Related to LL-37

Sources

Sources checked: 2026-10-18.

Information only, not medical advice. Peptifacts does not sell anything and does not link to sellers.