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Peptides

LL-37

Also called Cathelicidin LL-37, Human cathelicidin, hCAP18

Studied in:ImmuneTissue repairInflammation

Educational only, not medical advice. Dosaly reports what has been studied; it isn't a recommendation to use LL-37 or any amount of it. Talk to a clinician.

Not approved as a medicine by the FDA or EMA (as of October 2026).

Research applications

  • Bacterial membranes and biofilms (lab studies)
  • Inflammation and wound repair (lab studies)
  • Hard-to-heal venous leg ulcers (phase 2b topical trial, no overall difference from placebo)

What studies have looked at, not proven uses.

What it is

LL-37 is a natural peptide the body makes to fight germs. Lab studies show it can attack bacteria and affect healing. A human trial on leg ulcers didn't beat placebo overall.

More detail

LL-37 is a 37-amino-acid peptide and the only cathelicidin made by humans. It is cut from a larger precursor protein (hCAP18) and is produced by immune cells and by cells lining the skin and gut. It is part of the body's built-in defence against microbes: laboratory studies show it can disrupt bacterial membranes and biofilms, and it also influences inflammation and wound repair. In people, a phase 2b randomized trial tested a topical LL-37 product on hard-to-heal venous leg ulcers and found no significant difference from placebo in the whole group, with a possible signal in large ulcers that would need a further trial.

Evidence listed here

  • 1 human study
  • 2 reviews

Results from cells and animals often don't carry over to people. How to read peptide research

Molecular info

Class
Antimicrobial peptide (cathelicidin)
Length
37 amino acids
Sequence
H-Leu-Leu-Gly-Asp-Phe-Phe-Arg-Lys-Ser-Lys-Glu-Lys-Ile-Gly-Lys-Glu-Phe-Lys-Arg-Ile-Val-Gln-Arg-Ile-Lys-Asp-Phe-Leu-Arg-Asn-Leu-Val-Pro-Arg-Thr-Glu-Ser-OH
Research areas
Immune, Tissue repair, Inflammation

Cut from the larger precursor protein hCAP18.