LL-37
A naturally occurring human cathelicidin peptide studied for its antimicrobial and immune-modulating activity.
Overview
LL-37 is the only cathelicidin-family antimicrobial peptide naturally produced by humans, released from immune cells (particularly neutrophils) and epithelial tissue as part of the innate immune response. It’s named for its first two amino acids (leucine-leucine) and its 37-residue length.
Mechanism of Action
LL-37 disrupts microbial cell membranes directly through its cationic, amphipathic structure, giving it broad-spectrum antimicrobial activity against bacteria, fungi, and some viruses. Beyond direct antimicrobial action, it also functions as an immune-signaling molecule, recruiting and activating immune cells and influencing wound-healing processes — research has examined both of these roles somewhat independently.
Cited Research
Antimicrobial membrane disruption
Characterized LL-37’s cationic membrane-disrupting mechanism against a broad range of pathogens.
Innate immune signaling
Studied for its role in recruiting and activating immune cells beyond direct antimicrobial killing.
Wound healing research
Examined for effects on epithelial cell migration and angiogenesis during wound closure.
This is a summary, not an exhaustive review. Search the primary literature yourself: LL-37 on PubMed →
Safety & Handling
LL-37 should be handled only by qualified personnel in a laboratory setting, stored and reconstituted per its Certificate of Analysis, and kept refrigerated once reconstituted. It is not evaluated or approved by the FDA for any human or veterinary use.
Frequently Asked Questions
Is LL-37 naturally produced by the body?
Yes — it’s the only human cathelicidin peptide, naturally released by neutrophils and epithelial cells as part of innate immune defense.
Is LL-37 legal to purchase?
It’s legal to sell and purchase as a research chemical for laboratory use in the U.S. It is not approved by the FDA as a drug or supplement for human consumption.
How should it be stored?
Keep the lyophilized powder refrigerated or frozen prior to reconstitution. Once reconstituted, keep refrigerated and use within the timeframe on its Certificate of Analysis.
Is this page medical advice?
No. This page summarizes published literature for research and educational context only. It does not recommend a dose, protocol, or use in humans or animals outside a laboratory setting.
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