Claimed effect · LL-37

Does LL-37 help with antimicrobial action in people?

D
Grade D — no human evidence0 controlled · effect size: not measurable
Short answerNo human evidence. As of 3 September 2026, no controlled human trial has tested LL-37 for antimicrobial action in people. Kills bacteria in vitro and in animal models; no human trial has tested LL-37 as an anti-infective in any route.

What the studies show

Kills bacteria in vitro and in animal models; no human trial has tested LL-37 as an anti-infective in any route.

Animal studies, cell studies, or anecdotes only. This is where almost every viral peptide sits. Promising and proven are different words for a reason.

  1. 1
    Reviews of LL-37 biology in infection, wound repair and autoimmunity.VariousPreclinical mechanism; no systemic human data.

In context

LL-37 is the only cathelicidin peptide humans make — a 37-amino-acid antimicrobial produced by skin, gut and immune cells that kills bacteria and signals inflammation and repair. The human evidence is two randomised trials of a topical gel on venous leg ulcers: a 34-patient phase 2a that found faster healing, and a 148-patient phase 2b that did not, except in a subgroup of large wounds. Nothing supports the injected 'immune' or 'anti-inflammatory' uses sold online, and injected LL-37 is pro-inflammatory in the laboratory.

LL-37 is not approved. Legal status differs by country — see the regulation section or the jurisdiction pages.

Questions

Is LL-37 proven to help with antimicrobial action in people?
No. There is no human evidence for it (0 controlled); the claim rests on animal or cell studies and LYO grades it D.
What studies are behind the grade?
Kills bacteria in vitro and in animal models; no human trial has tested LL-37 as an anti-infective in any route.
Is LL-37 approved for this?
No. LL-37 is not approved; it is not an approved medicine for any indication in the jurisdictions LYO covers.

Other outcomes for LL-37

Reviewed 3 September 2026. Grades count human evidence only; see how LYO grades. Not medical advice. Correct this page →