37AA Limited Human
LL-37
The only human cathelicidin — an endogenous antimicrobial peptide that punches holes in bacterial membranes, recruits immune cells, and signals tissue repair.
In Plain English: LL-37 is the only cathelicidin peptide the human body naturally makes. It acts like a first-responder at infection sites — punching holes in bacterial membranes, recruiting immune cells, and signalling tissue repair. Clinical trials show it can triple wound-closure rates in large venous leg ulcers. Injectable use in humans has no clinical trial data yet.
Research Maturity
Limited Human (2,467 results on PubMed for 'LL-37' (verified 2026-05-04)+ Studies)
Quick Facts
Focus
Barrier Integrity
Infection & Immunity
Skin & Wound Repair
Route
Inhaled
Local Injection
Topical
Origin
Endogenous human host-defence peptide cleaved from precursor hCAP-18 by protease-3. Expressed in neutrophils, epithelial cells, macrophages, and keratinocytes in response to infection, injury, or UV. The sole human cathelicidin.
Mechanism
Cationic amphipathic alpha-helix acting via: (1) membrane disruption of microbial lipid bilayers; (2) LPS/LTA neutralisation blocking TLR4 while chaperoning nucleic acids to TLR3/7/8/9; (3) FPR2/ALX-mediated immune cell chemotaxis via NF-kB, MAPK/ERK, PI3K/Akt; (4) VEGF-driven angiogenesis and EGFR-mediated re-epithelialisation.
Outcome
Phase IIb RCT (N=149): topical 0.5 mg/mL achieved 28.1% complete closure vs 8.1% placebo in large ulcers (>=10 cm2); 3x placebo healing rate. Broad in-vitro antimicrobial activity against >38 bacterial species, 16 fungi, 16 viruses.
Safety Flags & Warnings
Pro-Tumorigenic at Physiological Concentrations
Autoimmune Exacerbation Risk
Zero Injectable Human Safety Data
Inverted Dose-Response
Bacterial Resistance Can Develop
Always consult a licensed physician. Research purposes only.
€12.5 / mg
