Recovery & healing
LL-37
Endogenous antimicrobial and immunomodulatory peptide with evidence for topical wound healing and emerging systemic applications.
FDA Category 1 bulk drug (compounding-pharmacy use only) Recovery & healing Anti-aging
- Full name
- Human Cathelicidin Antimicrobial Peptide 37
- Also known as
- cathelicidin LL-37, hCAP18
- Regulatory status
- FDA Category 1 bulk drug (compounding-pharmacy use only) | Investigational for systemic use
Origin
The sole cathelicidin antimicrobial peptide encoded by the human genome, produced by neutrophils and epithelial cells, cleaved from the hCAP18 precursor. Studied for three decades as a bridge between innate and adaptive immunity, now explored for wound healing and infection.
Mechanism
Direct antimicrobial activity via amphipathic alpha-helical membrane disruption of bacteria, fungi, and enveloped viruses. Also signals through FPRL1 to recruit immune cells, and promotes keratinocyte migration/angiogenesis for tissue repair.
Research summary
Evidence
The strongest human clinical evidence of this batch. A Phase IIb trial in venous ulcer patients found complete wound closure in 28.1% on LL-37 vs 8.1% placebo in large-wound subgroups. A diabetic foot ulcer trial showed greater granulation and faster closure. However, LL-37 complexes with self-DNA in psoriasis pathogenesis and drives rosacea inflammation, and pro-tumorigenic activity has been documented in several cancers; exogenous use may exacerbate both.
Evidence tier: FDA Category 1 bulk drug (compounding-pharmacy use only) — see the methodology note for how this is assessed.
Citations
Reported benefits
- enhanced venous/diabetic ulcer closure
- antimicrobial activity against bacteria/fungi/viruses
- promotion of angiogenesis and keratinocyte migration
Dosing protocols reported in the literature & community
These are protocols reported by compounding pharmacies, published trials, or self-experimentation communities — not a prescription. Start low, especially for anything new.
| Route | Reported protocol |
|---|---|
| Topical cream/gel (wound application) | Clinical trials used 0.5-1.6 mg/mL applied topically 2-3x weekly for 8-13 weeks. |
Side effects
- topical: local skin reactions (erythema, irritation)
Safety notes
Community & reddit notes (anecdotal — not clinical evidence)
Used primarily in clinical/compounding-pharmacy wound-care contexts. Some functional-medicine practitioners theorize intranasal benefits, but this is speculative. Because LL-37 is itself part of the innate immune system's own antimicrobial-peptide arsenal, some caution that introducing it exogenously can trigger an inflammatory response — another reason people who do try it tend to start at low doses.
Related peptides
Mixing compatibility
Pulled from a community-charted mixing-compatibility reference (anecdotal, clinic-use, and community-reported signals) — not a safety guarantee. Verify independently before combining anything.