LL-37: The Host-Defense Peptide Researchers Are Studying
LL-37 is the human body's best-known antimicrobial peptide, and it has become a frequent subject of immunology and tissue-repair research. This overview explains what LL-37 is, what makes it unusual, and what the research describes — strictly for educational and research context.
What LL-37 actually is
LL-37 is the only member of the cathelicidin family of antimicrobial peptides found in humans. It is a 37-amino-acid peptide (named for its two leading leucine residues) produced naturally by immune and epithelial cells as part of the innate immune system's first line of defence.
Why it's of research interest
LL-37 is studied because it is genuinely multifunctional. Beyond direct antimicrobial activity against bacteria, fungi and some viruses, research has examined its roles in modulating inflammation, supporting wound healing and angiogenesis, and bridging innate and adaptive immune responses. That breadth makes it a compelling model peptide for host-defence research.
What the research explores
Research models have explored LL-37 in the context of antimicrobial activity, immune signalling and tissue repair. Its dual nature — antimicrobial yet immunomodulatory — is a particular focus, as is the balance between its protective effects and its involvement in certain inflammatory processes. It remains an active, early-tier research area.
Handling and preparation
LL-37 is supplied as a lyophilised powder, kept cold and protected from light, then reconstituted for laboratory work. Our reconstitution guide and the on-site peptide calculator walk through preparing a solution and calculating concentration. Every batch ships with a per-batch Certificate of Analysis so identity and purity can be verified.
Important context
This article summarises published research for educational purposes only. LL-37 is supplied strictly for laboratory and research use only — not for human or veterinary use, consumption, or injection. Nothing here is medical advice, a recommendation, or a dosing protocol. The mechanisms described are research findings, not approved claims, and researchers are responsible for safe handling and compliance with applicable laws.
The bottom line
LL-37 is the human cathelicidin antimicrobial peptide, studied for a rare combination of antimicrobial and immunomodulatory activity that makes it a central model in host-defence and tissue-repair research. As with everything we carry, our LL-37 comes with full batch documentation and a verifiable COA.
Research use only. Educational content, not medical advice.