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Human cathelicidin antimicrobial/immune host-defense peptide (37 amino acids)

LL-37

Research use only

Written by pep4U Editorial Team · Last reviewed July 8, 2026

LL-37 is the body's own antimicrobial peptide, studied for killing microbes, calming or directing immune responses, and helping wounds heal.

Class / typeHuman cathelicidin antimicrobial/immune host-defense peptide (37 amino acids)
CategoryHealing, Recovery & Immune
Status (Jul 2026)Research use only

How it works

As the only human cathelicidin, it disrupts bacterial, fungal, and viral membranes directly and also acts as an immune signal, modulating inflammation, recruiting immune cells, and promoting angiogenesis and tissue repair.

Known / used for

Researched for chronic and diabetic wound healing, skin/mucosal antimicrobial defense, and immune modulation; a phase IIb topical wound-healing trial reported improved closure of large wounds versus placebo.

Positives

Broad antimicrobial activity (including drug-resistant organisms), pro-healing and angiogenic effects, and immune-modulating potential; endogenous molecule with active human wound-healing data.

Negatives & risks

Not an approved drug; can be pro-inflammatory and cytotoxic to host cells at higher concentrations, and elevated levels are linked to rosacea and psoriasis. Injectable/systemic use is unstudied for safety, and product purity is unregulated.

Frequently asked questions

What is LL-37?
LL-37 is the body's own antimicrobial peptide, studied for killing microbes, calming or directing immune responses, and helping wounds heal. As the only human cathelicidin, it disrupts bacterial, fungal, and viral membranes directly and also acts as an immune signal, modulating inflammation, recruiting immune cells, and promoting angiogenesis and tissue repair.
What is LL-37 used or researched for?
Researched for chronic and diabetic wound healing, skin/mucosal antimicrobial defense, and immune modulation; a phase IIb topical wound-healing trial reported improved closure of large wounds versus placebo.
Is LL-37 FDA-approved or legal?
NOT FDA-approved for any indication. As of 2026 it is treated as research-use-only and is available only through licensed compounding channels.
What are the main risks or downsides of LL-37?
Not an approved drug; can be pro-inflammatory and cytotoxic to host cells at higher concentrations, and elevated levels are linked to rosacea and psoriasis. Injectable/systemic use is unstudied for safety, and product purity is unregulated.

Legal / regulatory status

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