watchAnecdotalMay 3, 2026
Safety-risk caution
LL-37 appears in peptide access conversation as a compound where antimicrobial appeal collides with FDA safety-risk cautions.
FDAhigh confidencemedia
Source LL-37
Cathelicidin · hCAP-18
ImmuneTissue RepairNot ApprovedPhase IIIResearchSubQ
Popular for:Antimicrobial, immune modulation, wound healing
20
Registered Trials
58
Trial Publications
2,458
PubMed References
Phase III
Evidence Level
Overview
LL-37 is a 37-amino acid antimicrobial peptide and the only human cathelicidin. The short version: people usually care about it for antimicrobial, immune modulation, wound healing, but the strength of the evidence depends heavily on indication and study type.
LL-37 is a 37-amino acid antimicrobial peptide and the only human cathelicidin. It is a key component of the innate immune system, produced by immune cells, epithelial cells, and other tissues in response to infection or injury. LL-37 was first identified from human neutrophils and is encoded by the CAMP gene.
Beyond its direct antimicrobial activity, LL-37 functions as an immunomodulator, wound healing promoter, and anti-biofilm agent. It is studied for its broad-spectrum antimicrobial effects against bacteria, viruses, and fungi, as well as its role in tissue repair and immune regulation.
Research Snapshot
What the evidence says
Phase IIILL-37 currently shows 20 registered trials from ClinicalTrials.gov, 58 PubMed trial publications (37 RCT-tagged), and 2,458 PubMed references matching the stored source query. Treat PubMed references as literature surface area, not a count of clinical trials.
Known vs uncertain
Known signals
- 20 registered trials are tracked from ClinicalTrials.gov intervention records.
- 58 PubMed clinical-trial publications are indexed.
- 37 PubMed randomized controlled trial publications are indexed.
- 2,458 PubMed references are tracked separately from trial counts and can include animal, in-vitro, review, mechanism, or clinical records.
Open questions
- Evidence strength may vary by indication, route, formulation, and population.
- Public anecdotes can highlight interest or concern but do not establish clinical efficacy.
- Regulatory status and compounding access can change independently from the research literature.
Mechanism of Action
LL-37 disrupts microbial membranes through electrostatic interaction with negatively charged pathogen surfaces, creating pores that kill bacteria, fungi, and enveloped viruses.
Key Research Benefits
Broad-spectrum antimicrobial (bacteria, fungi, viruses)
Anti-biofilm activity (disrupts bacterial biofilms)
Studied for wound healing and tissue repair
Immunomodulatory — balances immune response
Researched for Lyme disease and chronic infections
Neutralizes bacterial endotoxins
Clinical Evidence Summary
Research Pipeline
Preclinical
Animal
Phase I
Phase II
Phase III
Approved
20
Registered Trials
58
Trial Publications
37
RCT Publications
2,458
PubMed References
ClinicalTrials.govPubMed ESearchExact-name queryChecked May 3, 2026
Registered trials are ClinicalTrials.gov intervention records. Trial publications are PubMed records tagged as clinical trials or randomized controlled trials. PubMed references are broader source-query matches and can include animal studies, in-vitro work, reviews, mechanism papers, and trial publications.
20
Registered trials
58
Trial publications
37
RCT publications
2,458
PubMed references
244
Reviews
3
Meta-analyses
Registered trials source
Jun 1, 2026
LL-37
Uses the exact compound name as a ClinicalTrials.gov intervention query.
View sourceNot FDA-approved as exogenous therapeutic. LL-37 is a naturally occurring human peptide. Research compound. Active area of study in antimicrobial resistance and wound healing.
Key PubMed References
2,458 PubMed references · showing top 25 by relevance
View all on PubMedHuman antimicrobial/host defense peptide LL-37 may prevent the spread of a local infection through multiple mechanisms: an update.
In Vitro
Svensson D, Nilsson BO · Inflammation research : official journal of the European Histamine Research Society ... [et al.] · 2025
PMID: 40063262Vitamin D triggers hCAP18/LL-37 production: Implications for LL-37-induced human osteoblast cytotoxicity.
Review
Aidoukovitch A, Bankell E, Svensson D, et al. · Biochemical and biophysical research communications · 2024
PMID: 38642493Cathelicidin peptide LL-37: A multifunctional peptide involved in heart disease.
Review
Miao S, Liu H, Yang Q, et al. · Pharmacological research · 2024
PMID: 39615616The LL-37 domain: A clue to cathelicidin immunomodulatory response?
Review
Leite ML, Duque HM, Rodrigues GR, et al. · Peptides · 2023
PMID: 37068711Serum LL-37 and inflammatory cytokines levels in psoriasis.
Human Study
Lao J, Xie Z, Qin Q, et al. · Immunity, inflammation and disease · 2023
PMID: 36988247Anecdotes & Sentiment
Public discussion, not clinical evidence
This section summarizes what people are talking about in public sources. It can be useful for spotting questions, hype cycles, and recurring concerns, but it is separate from the evidence sections above.
Side Effects & Safety
- Injection site reactions - Potential for mast cell activation at high concentrations - Limited human dosing data for exogenous administration - May cause histamine-related effects
Injection site reactions
Potential for mast cell activation at high concentrations
Limited human dosing data for exogenous administration
May cause histamine-related effects
Known Interactions
No curated interaction entry is live for LL-37 yet.
Until the interaction table is fully populated, use the interaction checker and related peptides below to explore adjacent compounds and likely research pairings.
Comparison Pages
Comparison pages
AllNo comparison page is linked yet.
Frequently Asked Questions
Research Disclaimer
This page is for research and educational purposes only. The information presented is based on published scientific literature and does not constitute medical advice, diagnosis, or treatment recommendations. Regulatory status can vary by compound, formulation, indication, and jurisdiction. Check official labeling, registry records, and qualified professional guidance before making any health-related decision. The studies referenced are linked to their original PubMed sources for verification.