LL-37

Research Only

Antimicrobial Peptides · Immune Defense

LL-37 is the only human cathelicidin antimicrobial peptide, playing a key role in innate immune defense.

What is LL-37?

LL-37 is the only human cathelicidin antimicrobial peptide, playing a key role in innate immune defense. It has broad-spectrum antimicrobial activity against bacteria, viruses, and fungi, and also modulates the immune response, wound healing, and inflammation.

Also known as: Cathelicidin, CAP-18

How Does LL-37 Work?

Disrupts microbial cell membranes through direct interaction with lipid bilayers. Also modulates immune responses by recruiting immune cells, promoting autophagy, neutralizing endotoxins, and regulating cytokine production. Promotes wound healing through keratinocyte migration and angiogenesis.

What is LL-37 Used For?

Antimicrobial defense
Immune modulation
Wound healing
Biofilm disruption

Potential Side Effects

Injection site pain
Redness at injection site
Mild fever (rare)

Contraindications

Autoimmune conditions
Pregnancy

FDA Legal Status

United States — FDA

Research Only

This peptide is currently investigational and not approved for clinical use.

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Frequently Asked Questions

What is LL-37 used for?

LL-37 is used for its broad-spectrum antimicrobial and immune-modulating properties. It can help fight bacterial, viral, and fungal infections, disrupt biofilms, and support wound healing. It is particularly interesting for antibiotic-resistant infections.

Quick Facts

Legal Status (USA): Research Only
Evidence Rating: CPreliminary Evidence (Mostly Preclinical)
Class / Subclass: Antimicrobial Peptides / Immune Defense
Administration: subcutaneous, topical
Typical Dosage: 100-200mcg daily
Half-Life: ~4-6 hours
Year Discovered: 1995

Sources

PubMed 14675457

Last updated: 2026-04-01

Sources & references

Primary sources used for the dosing, mechanism, side-effect, and regulatory claims on this page. Verify time-sensitive information (regulatory status, prescribing details) on the source before relying on it for medical decisions. See our disclaimer.

PubMed PMID 14675457 — peer-reviewed primary literature on LL-37.
FDA Federal Register — official notice record for FDA regulatory actions and Category 1 / 503A bulk-substance updates.