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LlHuman trials

LL-37 protocol

LL-37 is a natural germ-fighting peptide made by the body. In people it has been tested only as a gel on leg ulcers that would not heal. It is not an approved medicine, and we found no trial of injected LL-37.

Not approved as a medicine by the US FDAHuman trials: gel on leg ulcers (phase 1/2 and phase 2b)No trial of injected LL-37 found
ProtocolMixingResultsSide effectsHow it worksSources

The protocol at a glance

In the first human trial, LL-37 gel was applied to the ulcer twice a week for 4 weeks at 0.5, 1.6 or 3.2 mg/mL. The lower strengths worked best.

TrialAmount and schedule
Human injection doseNot established
Phase 1/2, venous leg ulcers (34 people)Gel at 0.5, 1.6 or 3.2 mg/mL, applied twice a week for 4 weeks
Phase 2b, venous leg ulcers (148 people)Gel at 0.5 or 1.6 mg/mL, together with compression bandaging

Grönberg 2014 and Mahlapuu 2021. Both were gels applied to the wound, not injections. The phase 2b abstract does not state how often the gel was applied.

Community reports

Community reports commonly describe 100 to 200 mcg a day under the skin. These are user reports, not trial doses.

What people say they do, collected from community discussions. Not tested in a trial; shown so you can compare it with the evidence above.

Mixing

No mixing table here: this one is used as a capsule, nasal spray or skin product, or has no human amount to calculate from. The general mixing calculator works for any vial.

What the trials found

Phase 1/2 trial, 34 people with hard-to-heal venous leg ulcers, 4 weeks of treatment. What was measured: how much the ulcer shrank.

68%average ulcer shrinkage at 0.5 mg/mL
50%average ulcer shrinkage at 1.6 mg/mL
Nonedifference from placebo at 3.2 mg/mL
148people in the larger phase 2b trial, which found no significant healing gain overall

Grönberg A et al. Wound Repair Regen 2014 (PMID 25041740); Mahlapuu M et al. Wound Repair Regen 2021 (PMID 34687253). In the phase 2b trial a later subgroup look suggested a benefit for ulcers of 10 cm2 or more; that was not the main result.

Side effects

  • No safety concerns were found for local or whole-body side effects in the first trial.
  • The gel was well tolerated in the phase 2b trial.
  • These results are for gel on the skin. Injected LL-37 has no human safety data that we found.

How it works

Natural germ-fighting peptide

LL-37 is part of the body's own defence against germs. Researchers tested it on chronic wounds to see if it helps them close.

Sources

  • Grönberg A et al. Wound Repair Regen 2014 (phase 1/2), PMID 25041740
  • Mahlapuu M et al. Wound Repair Regen 2021 (phase 2b, HEAL LL-37), PMID 34687253
  • Drugs@FDA / openFDA search: no LL-37 product