Where the claims come from
The science behind the interest is genuine, and it includes a well-known link to vitamin D, which increases the body’s own production of LL-37. That connection is often presented as evidence that supplementing the peptide will improve immunity or heal wounds, which is a different claim from the one the research supports.
What evidence exists outside the registry
This is a compound where the registry count understates the human evidence. At least three controlled human trials have been published without a registry entry, covering venous leg ulcers, diabetic foot ulcers and an oral preparation studied against SARS-CoV-2. Separately, most trials that appear in a naive registry search do not administer LL-37 at all — they measure it as a marker in vitamin D studies.
- LL-37 in venous leg ulcers (Wound Repair Regen, 2021) — Multicentre randomised trial; published without a ClinicalTrials.gov registration.
- NCT02225366 — intratumoral LL-37 in melanoma — One of only two registered trials that administer the peptide.
- FDA — bulk drug substances nominated but withdrawn — Cathelicidin LL-37 appears in the withdrawn table.
Approved for, studied for, sold for
Three separate lists, kept by three separate processes: a regulator decides the first, researchers the second, and whoever is selling it the third. They are often not the same list, and the differences are the most useful thing on this page.
Not approved by the FDA for any use. Nothing has been reviewed for safety, effectiveness or manufacturing quality.
- Diabetic Foot Ulcer
- Melanoma
- Wound healing
- Antimicrobial
- Immune support
- Skin
Is it studied for what it's sold for?
Each claim below is matched against the condition and title fields of every registered trial. Not listed means no trial names it as a studied condition — not that it has been disproven, and not that no trial touches it indirectly.
Every trial on record
Every registered human study we can find for LL-37. Click any ID to read the original record — we would rather you checked us than trusted us.
| Trial ID | Title | Condition | Phase | Status | Enrolled |
|---|---|---|---|---|---|
| NCT02225366 | Intratumoral Injections of LL37 for Melanoma | Melanoma | Phase 2 | Completed | 4 |
| NCT04098562 | Efficacy of LL-37 Cream on Bacteria Colonization, Inflammation Response and Healing Rate of Diabetic Foot Ulcers | Diabetic Foot Ulcer | Phase 2 | Status not updated | 40 |
What regulators have said
Compounded drugs containing cathelicidin LL-37 may pose risk for immunogenicity for certain routes of administration and may have complexities with regard to peptide-related impurities and API characterization. FDA lacks sufficient safety-related information regarding cathelicidin LL-37.
A withdrawn nomination means the substance was proposed for use in pharmacy compounding and the proposal was later pulled, so it is not on FDA's active list. FDA had published the concern above while it was under review. Neither the concern nor the withdrawal is a finding about whether LL-37 works.
Why sources disagree on this number
Different sites publish different counts for LL-37 because they are answering different questions. Here is every way of counting the same set of studies, so you can see which rule produces which number.
That is accurate under a specific definition. 2 registered human trials exist, but none enrol 100 or more people. Both statements describe the same registry. They differ only in what counts as "large".
Sources that count only completed studies get 1. We count registered trials at any status, because a trial that is recruiting is still a real trial and is the thing most likely to change this page. Neither number is wrong; they answer different questions.
For "how much human evidence exists", 2 is the honest answer, with the caveat that 1 has actually finished. Every trial is listed on this page with its ID — if you disagree with how we count, you can recount it yourself in about a minute.
Common questions about LL-37
How many human trials does LL-37 have?
2. That is the number of registered interventional human studies we can find, each listed on this page with a link to its original record.
Is LL-37 FDA approved?
No. LL-37 is not approved by the FDA for any indication. Compounded or "research use only" preparations are not FDA-approved and receive no premarket review for safety, effectiveness, or manufacturing quality.
What is LL-37 actually being tested for?
Registered studies cover: melanoma, diabetic foot ulcer. Compare that to what it is marketed for — the two lists are often different, which is the whole point of this page.
Where does this data come from?
ClinicalTrials.gov, the US public registry of clinical studies. We count interventional human studies only — observational studies are not evidence of effect. Every trial on this page links to its original record so you can check us rather than trust us.
More on LL-37: how many human trials it has · is it FDA approved · has it been studied for safety · what it is studied for
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