LL-37

Overview

LL-37 is the only cathelicidin-family antimicrobial peptide identified in humans, cleaved from a larger precursor protein (hCAP18) and naturally expressed in skin, immune cells, and mucosal surfaces as part of the innate immune system's defense against pathogens.

Proposed Mechanism of Action

LL-37 disrupts bacterial cell membranes directly (a mechanism shared by many antimicrobial peptides), while separately promoting keratinocyte migration and re-epithelialization during wound healing — the combination of antimicrobial and pro-healing activity is what makes it of particular research interest for chronic, infected wounds like diabetic foot ulcers, where biofilm-forming bacteria complicate healing.

Research Context

The cited review synthesizes evidence that LL-37 both disrupts bacterial biofilms (structured bacterial communities that resist normal antibiotic treatment) and independently promotes tissue repair — proposing it as a candidate therapeutic specifically for polymicrobial infected wounds. It's a review of the mechanistic and preclinical evidence rather than a single clinical trial.

Limitations of the Current Evidence

• We cited a review rather than a primary trial; if you need dosing or trial-level detail, follow the review's references to the underlying preclinical studies.
• LL-37 also has documented roles in inflammatory skin conditions (notably psoriasis, where it can act as an autoantigen) — its biology is genuinely double-edged, and "more LL-37 is better" is not a safe assumption to carry away from the wound-healing literature alone.