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Peptide Evidence Registry

Immune & inflammation · Tissue repair

LL-37

A human antimicrobial peptide studied topically for wound healing, now marketed for unrelated systemic uses.

L3Early human studiesNot approved for this useStalled
How settled this rating is:
very-low confidence in the current evidence rating
Routes studied:
Not established · Topical, Subcutaneous injection, Nasal (marketed but never approved)
Also known as:
cathelicidin, hCAP-18 fragment, antimicrobial peptide
Last reviewed:
2026-09-06
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Evidence passport

LL-37

A one-screen evidence identity for this compound. These fields describe research maturity, confidence and legal status. They are not a safety guarantee, efficacy percentage or recommendation.

Reviewed 2026-09-06
Evidence level
L3Early human studies
Confidence
Very low confidence in rating
Regulatory status
Not approved for this use
Development status
Stalled

Evidence strength

Human efficacy evidence22 of 100 evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Human safety evidence18 of 100 evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

The 0-100 values rate the strength and maturity of evidence, not how effective or safe the compound is.

Evidence base
Mostly animal and laboratory research
Furthest established stage
Phase II
Human research maturity
Phase II/IIb topical wound studies completed; primary outcome not met in the larger study
Source curation
Sources fully curated

Routes recorded

Topical· unapprovedSC injection· unapprovedNasal· unapproved

Most of this evidence comes from animals and cells

The supporting research for LL-37 is predominantly preclinical (Level 1–2). That is a legitimate starting point for science and a poor basis for personal decisions. Human results are not simply a scaled-up version of mouse results.

Overview

Human efficacy evidence strength22 of 100 evidence strength

Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.

Preclinical (animal / lab) evidence strength60 of 100 evidence strength

Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.

Human safety evidence strength18 of 100 evidence strength

Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number.

How to read these scores

Every number here rates the evidence, not the compound. They are editorial 0-100 strength ratings, not percentages, and not a rating out of five stars.

  • Human efficacy evidence strength — Higher = more and better-quality human evidence. It does not mean the effect is bigger or that the compound works for you.
  • Preclinical evidence strength — Higher = more animal, tissue or cell research. Preclinical results are a starting point, not proof of a human benefit.
  • Human safety evidence strength — Higher = more mature, better-documented human safety data. It does not mean the compound is safer than one with a lower number. A score of 80 does not mean “80% safe”.
  • Evidence level (L0-L5) — the strongest type of study behind the compound, from anecdote (L0) to large replicated human trials (L5). It is a description of the study evidence, not a quality, safety or recommendation rating.
  • Confidence — how likely we think it is that this rating changes as new research lands. Low confidence means the picture is unsettled, not that the compound is bad.

None of these ratings is medical advice, a safety guarantee, or a recommendation to use anything. How we grade evidence.

How far human research has progressed: Phase II/IIb topical wound studies completed; primary outcome not met in the larger study

Routes & formulations

Marketed / research routes — never approved

Topical· unapprovedSC injection· unapprovedNasal· unapproved

Human trials used topical application to wounds. Injectable and nasal products sold online are a different proposition entirely — a topical wound result says nothing about systemic dosing.

Route availability is not evidence of efficacy, and evidence from one route does not transfer to another. The Registry never provides dosing or sourcing information.

Peptide lifecycle

  1. Discovery

  2. Preclinical

  3. Phase I

  4. Phase II

    Development stopped here — a programme status, not a safety verdict.

  5. Phase III

  6. Approved

Stalled

A Phase IIb study in hard-to-heal leg ulcers did not show a significant overall benefit, after earlier smaller work reported signals. Our record does not establish an active late-stage programme.

Why development stopped: Did not meet endpoints. Trials failed to show the benefit they were designed to detect.

Last documented development: Phase IIb topical leg-ulcer study published 2021

What it is

A naturally occurring human cathelicidin peptide with antimicrobial and immune-signalling activity, produced as part of innate defence in skin and mucosa.

What people claim

  • Heals chronic wounds
  • Treats resistant infections
  • Resets or boosts the immune system when injected

What the evidence actually says

There are two completely different LL-37 stories, and they get blended online. One is a legitimate topical wound-healing research programme: earlier small work showed encouraging signals, then a Phase IIb study in hard-to-heal leg ulcers did not show a significant overall benefit. The other is systemic biohacking use, which has no supporting human trials at all. A peptide being part of human immunity is not evidence that injecting it helps anything.

Related evidence

Useful next reads based on this compound — not recommendations.

Human evidence

  • Phase IIb randomised study of topical LL-37 in hard-to-heal venous leg ulcers did not demonstrate a significant overall benefit (2021).
  • Earlier smaller topical work reported healing signals that the larger study did not confirm.
  • No adequate human evidence for systemic, injectable or nasal use.

Preclinical evidence

  • Extensive laboratory work on antimicrobial membrane activity, chemotaxis and immune modulation.
  • Animal wound and infection models with mixed translation to human outcomes.

Animal and cell findings are Level 1–2 evidence.

Mechanism and pathways

  • Direct antimicrobial activity through microbial membrane disruption.
  • Host immune signalling, chemotaxis and angiogenesis effects — dose- and context-dependent, and pro-inflammatory in some settings.

Safety and unknowns

  • Local irritation reported with topical use; systemic human safety data are absent.
  • LL-37 has been implicated in inflammatory skin disease biology, so 'more is better' reasoning is not safe reasoning.

Cancer relevance

This section covers questions raised by how the compound works in the body, plus anything regulators and trial teams keep an eye on. It is not a statement that this compound causes cancer — for most compounds here, no human data exist in either direction.

Theoretical / mechanistic concern only

Laboratory work reports both tumour-promoting and tumour-suppressing effects depending on tissue. Nothing is established in humans; the honest position is unresolved.

Regulatory status

Regulatory decisions apply to specific jurisdictions, products, formulations and indications. An approval elsewhere is not automatically an approval in your country.

Check the regulatory note and linked primary sources for jurisdiction-specific details.

Not an approved medicine. Its clinical study history is topical, in hard-to-heal wounds. Injectable or systemic use for infections, 'immune reset' or biohacking purposes is unstudied. Compounding-nomination status has changed during 2026 and should be read cautiously.

Evidence grade

L3Early human studiesVery low confidence in rating

Preliminary human outcome research, including small or observational studies. Descriptive exposure studies alone do not demonstrate therapeutic benefit.

What would change our rating?

  • A positive, adequately powered topical wound trial.
  • Any human safety or pharmacokinetic data for systemic administration.

References and sources

Source transparency

A provenance snapshot of this profile. Counts show what kinds of sources are cited, not how much scientific weight each source deserves.

Sources fully curated
Last editorial review
2026-09-06
Recently reviewed · 45 days ago
Linked curated sources
2
Sources still pending
0
External specialist reviews
0
None recorded for this profile
Regulatory / label: 1Peer-reviewed: 1

Review provenance

Registry editorial review: Colin Jackson-White, creator and editor, who is not a doctor or clinician. External specialist review is credited only when a named reviewer has completed a review of this exact profile.

Literature-discovery and AI tools may help locate or challenge candidate evidence, but they are not counted as evidence sources here. Registry judgements are tied to the underlying papers, trial records, regulator documents and official study records.

Source hierarchy: regulatory documents and trial registries first, peer-reviewed work next, sponsor material flagged as non-independent. We never use supplier or clinic marketing as evidence, and where a verified source has not yet been curated we say so rather than inventing one.

Evidence change history

These entries record changes to our assessment of the published evidence — not changes to the compound itself.

No recorded changes yet. Baseline position set on 2026-09-06.