Gathering the record
Relay is organizing the evidence and source boundaries.
Human cathelicidin antimicrobial peptide
LL-37 is an innate-immune peptide studied for antimicrobial, inflammatory, and wound-healing biology.
60-Second Overview
Start with what it is, why it matters, what research has shown, and what remains unknown. The science follows after the orientation.
Start here. These four answers explain why the compound matters before the page introduces the deeper science.
LL-37 is a peptide made by the human immune system. It can interact with microbial membranes while also influencing inflammation, cell movement, and tissue-repair signaling.
That combination makes LL-37 relevant to wound, infection, immune, and cancer research. The same broad biological activity also creates safety questions because helpful and harmful effects may depend on tissue, concentration, and disease context.
A small randomized study tested topical LL-37 in hard-to-heal venous leg ulcers and reported dose-dependent healing signals over four weeks. Early intratumoral melanoma research explored immune changes but did not establish general anticancer benefit.
Whether the wound signal reproduces in larger trials, how durable it is, and whether systemic exposure is safe remain unresolved. Pro-inflammatory, cell-toxic, and context-dependent tumor biology prevent broad conclusions from one topical study.
The research depth, routes, studies, and primary sources below explain how Relay knows—and where the evidence stops.
Research context
Published research has investigated this compound using the following study designs.
These records explain what researchers did. They are not instructions, recommendations, or a transferable protocol.
A randomized, blinded study investigated topical LL-37 in adults with hard-to-heal venous leg ulcers, comparing several study concentrations with placebo.
Reported study administration—not a recommendation.
Research at a glance
Evidence depth, confidence, and route context explain how Relay knows—not what anyone should do.
Early controlled human evidence in topical wound research; broader systemic claims remain preclinical.
Research depth describes how large and mature the overall record is. It does not tell you whether the results were positive.
Whether benefits reproduce in larger trials and how pro-inflammatory, cytotoxic, or context-dependent tumor-biology signals affect safety.
Confidence describes how reliable and consistent the conclusions are. It can be high for one outcome and low for another.
The strongest evidence type shows what the best-supported conclusions are actually based on.
Human findings are more directly relevant than animal or laboratory results, but they still apply only to the populations and outcomes studied.
Route-specific record
These are exposures used in cited research for a specific route and population—not an instruction for an individual.
Half-life describes how long it takes the measured amount in the body to fall by half. It is not a dosing recommendation.
Evidence can change by administration method. Findings from one route should not automatically be applied to another.
Evidence boundary: The study was small, short, topical, and limited to one difficult-to-heal wound population. It cannot establish infection treatment, systemic safety, cancer effects, or outcomes with injectable or other formulations. Amounts shown describe cited research exposure—not a dosage recommendation.
Detailed evidence
Start with the strongest supported conclusion and its main uncertainty. Claim-level records below show how the evidence changes by question, population, route, formulation, and study design.
A randomized topical venous leg ulcer study reported dose-dependent wound-healing signals over four weeks.
This is the strongest supported conclusion in the current human evidence—not a summary of every claim made about the compound.
Whether benefits reproduce in larger trials and how pro-inflammatory, cytotoxic, or context-dependent tumor-biology signals affect safety.
Keeping the main uncertainty visible prevents an early or promising finding from looking more settled than it is.
Questions people bring to the evidence
Research questions—not promises of benefit.
This is the strongest human-evidence boundary in the current record.
Mechanistic findings explain biological plausibility; they do not establish a human outcome.
Relay keeps this uncertainty visible rather than converting it into a prediction.
The safety snapshot reflects the studied record and its limitations.
Regulatory and identity status determine how the evidence should be interpreted.
Mechanisms
LL-37 interacts with microbial membranes and host immune and repair pathways. A topical venous-leg-ulcer study provides narrow human evidence; cancer, infection, and systemic-use questions remain unresolved.
A plausible mechanism can explain why a study was attempted. It does not prove that the compound improves a human outcome.
Studies
Study arms are reported for transparency. They describe what researchers did in a defined record and do not transfer across identities, routes, formulations, or populations.
A later trial phase can ask a more mature question, but it does not guarantee a positive result, regulatory approval, or relevance outside the studied population.
Randomized double-blind placebo-controlled study
Adults with hard-to-heal venous leg ulcers
Topical LL-37 was tested for four weeks in hard-to-heal venous leg ulcers, with dose-dependent healing signals.
Study administration: Topical LL-37 at multiple doses versus placebo
Limitations: Small, short, topical, indication-specific study.
Early translational clinical study
Adults with melanoma
Endpoints were not fully described in the current record.
Early intratumoral research explored immune effects in melanoma.
Study administration: Not stated in the current record.
Limitations: Does not establish general anticancer efficacy or systemic safety.
Laboratory and animal wound models
Population not stated.
Endpoints were not fully described in the current record.
Preclinical models support repair signaling hypotheses.
Study administration: Not stated in the current record.
Limitations: Preclinical effects do not establish clinical benefit.
Safety snapshot
Local reactions and the peptide’s concentration-dependent inflammatory or cytotoxic biology require indication- and formulation-specific study; systemic safety is not established.
Controlled human evidenceReported events depend on population, formulation, route, exposure, comparator, and study size.
Open sourceThe current record does not support a reliable common-versus-uncommon frequency split.
Evidence boundaryUnder-detected or under-reported events must not be described as rare.
No source-qualified compound-specific warning or contraindication is encoded in the current record.
Evidence boundaryInvestigational; no FDA-approved LL-37 product. Whether benefits reproduce in larger trials and how pro-inflammatory, cytotoxic, or context-dependent tumor-biology signals affect safety.
The current record does not identify a reliable compound-specific pattern of events that caused study discontinuation.
Evidence boundaryThis is an evidence gap, not proof that discontinuations did not occur.
No compound-specific patient-facing urgent-action threshold is established in the current Relay record.
Evidence boundaryRelay does not infer emergency guidance from study discontinuations, mechanism, or incomplete adverse-event reporting.
Community
Built by the community
Every structured report adds useful context about research setup, outcomes, and unwanted effects as the community dataset grows.
Publicly anonymous by default. Your account keeps reports editable and helps reduce duplicate submissions.Sources
PMID 25041740
PMID 29665030
PMID 21693141