LL-37

The C-terminal fragment of human cathelicidin antimicrobial protein hCAP18, LL-37 is the only cathelicidin peptide expressed in humans. It is released from neutrophils, macrophages, epithelial cells, and keratinocytes in response to infection and injury. LL-37 has multiple simultaneous mechanisms: direct antimicrobial activity (disrupts bacterial and fungal membranes), immune modulation (promotes macrophage differentiation, reduces excessive inflammation), wound healing promotion (activates epidermal growth factor receptor, promotes re-epithelialisation), and gut barrier restoration (upregulates tight junction proteins and promotes mucosal healing). Its dual role as both an antimicrobial and an immunomodulatory-wound healing agent makes it uniquely positioned in recovery and gut health protocols.

LL-37 is one of the most studied naturally occurring antimicrobial peptides in the human body. Over 500 published studies cover its antimicrobial, immunomodulatory, and wound healing properties. Multiple human trials demonstrate efficacy for chronic wound healing (venous leg ulcers, diabetic foot ulcers) when applied topically. A published Phase II trial demonstrated statistically significant improvement in venous leg ulcer healing versus placebo. Gut-specific research shows protection of intestinal epithelial cells from pathogen invasion and promotion of mucosal repair. Levels are known to be deficient in Crohn's disease, UC, and recurrent infection susceptibility. The clinical research trajectory is strong; systemic peptide administration for non-wound healing indications remains early-stage.

2–4 weeks for acute applications