PeptideImmunomodulatorAntimicrobial peptideCathelicidin

LL-37 (Cathelicidin)

Also known as Cathelicidin · hCAP18 fragment · CAMP

Written by enwyReviewed 5 Aug 20261 sources0 comments

The active fragment of the human cathelicidin antimicrobial protein hCAP18, a 37-residue host-defence peptide with broad antimicrobial, immunomodulatory and wound-healing roles. Widely studied as an endogenous molecule, but as an injected or topical therapeutic it is early-stage and mostly preclinical.

01 Overview

LL-37 is a naturally occurring cationic host-defence peptide expressed by neutrophils and epithelial cells. It disrupts microbial membranes, neutralises endotoxin, and modulates immune signalling and angiogenesis, making it central to innate immunity and skin barrier defence.

As a drug it is being explored for chronic wounds, infection and cancer, but human therapeutic data are limited. LL-37 is double-edged: the same properties that aid healing can drive inflammation, and it is implicated in rosacea and psoriasis, so exogenous use is not benign.

02 Mechanism

Cationic amphipathic peptide that permeabilises microbial membranes, neutralises LPS, and modulates immune cell chemotaxis, angiogenesis and wound repair.

03 Dosing

Tier	Dose	Route	Notes
Experimental	100–500 mcg	SubQ	No established human dose; grey-market figures are anecdotal and unvalidated.

04 Effects

Effect	Magnitude	Evidence
Antimicrobial activityKills bacteria, fungi and some viruses and neutralises endotoxin in laboratory studies.	Broad-spectrum in vitro	Preclinical
Wound-healing supportPromotes angiogenesis and keratinocyte migration in wound models; human therapeutic evidence is limited.	Enhanced re-epithelialisation (models)	Preclinical

05 Side effects

Effect	Severity	Frequency	Evidence	Countermeasures
Pro-inflammatory skin reactionsExcess LL-37 is implicated in rosacea and psoriasis flares; exogenous use may aggravate inflammatory skin conditions.	Moderate	Unknown	Preclinical
Cytotoxicity at high concentrationAt higher concentrations LL-37 can damage host cell membranes, not just microbial ones.	Moderate	Unknown	Preclinical

06 Legal status

United States

Research chemical

Endogenous peptide sold 'for research use only'; not an approved therapeutic. · as of Jan 2026

07 References

The human antimicrobial peptide LL-37: functions and therapeutic potentialPubMed (LL-37 cathelicidin review)

08 Discussion0 comments

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This page is reference information, not medical advice. Doses and protocols are documented as they appear in the clinical literature and in practice — describing them is not a recommendation to use them. Countermeasures listed here are not a substitute for a physician. Legal status varies by jurisdiction and changes.