LL-37

LL-37 - Human Cathelicidin Antimicrobial Peptide

LL-37 is the active 37-amino-acid C-terminal fragment of hCAP-18, the only cathelicidin peptide found in humans. It is released by neutrophils, epithelial cells, and skin in response to infection and injury, and is the subject of a large and active body of literature on antimicrobial defense, immunomodulation, and tissue repair. Unlike narrow-spectrum antibiotics, LL-37 is a broad-spectrum innate-immunity peptide - it interacts with bacterial membranes, viral envelopes, and host immune cells on the same scaffold.

Why LL-37’s Dual Profile Matters

LL-37 is studied for two distinct activities at the same time: a direct antimicrobial effect (it disrupts bacterial and viral membranes) and an immunomodulatory effect (it recruits and activates immune cells, and binds LPS to quiet endotoxin signaling). Most research peptides sit on one axis or the other. LL-37 sits on both - which is why it shows up in antimicrobial, wound-healing, and immunology literature all at once.

LL-37 vs KPV

LL-37 and KPV show up together in some anti-infection and anti-inflammatory study designs, so the distinction is worth noting.

Research Applications

LL-37 is used in studies examining:

• Broad-spectrum antimicrobial activity - bacterial, viral, and biofilm models
• Endotoxin (LPS) binding and neutralization
• Wound-healing and re-epithelialization
• Neutrophil and monocyte chemotaxis and activation
• Skin-barrier and psoriasis-relevant immune signaling
• Cathelicidin-family structure-activity relationship work

Specifications

Storage & Handling

Unopened vials are kept at 2-8°C under standard cold-chain conditions and remain stable for 12+ months. Reconstitution parameters, solvent compatibility, and post-reconstitution stability for LL-37 are documented in the published peer-reviewed literature and standard peptide-chemistry references.

Reference Literature

Published clinical and preclinical LL-37 literature is available through PubMed, Google Scholar, and other peer-reviewed databases. WWP does not provide protocol design, dosing guidance, or administration parameters. Those decisions rest with the researcher and any applicable institutional review board.

Common Questions About LL-37 Research

What does LL-37 do in research?

It is most commonly studied as a host-defense peptide with two parallel activities: direct antimicrobial action against bacteria, viruses, and biofilms, and immunomodulatory effects including LPS binding, immune-cell recruitment, and wound-healing signaling.

What is the difference between LL-37 and KPV?

LL-37 is a 37-amino-acid cathelicidin with both direct antimicrobial and immunomodulatory activity. KPV is a 3-amino-acid alpha-MSH fragment with anti-inflammatory activity only and no direct antimicrobial profile. They are sometimes paired in study designs where both antimicrobial and anti-inflammatory endpoints are being tracked.

What diseases is LL-37 studied in?

Published research covers bacterial and viral infection models, chronic wound and diabetic ulcer models, psoriasis and skin-barrier research, inflammatory bowel models, and cancer-biology work examining cathelicidin expression. LL-37 is a discovery-stage peptide - it is not an approved therapeutic.

Is LL-37 FDA approved?

No. LL-37 is not approved by the FDA for any human use. Every vial WWP ships is labeled and sold strictly for laboratory and research use only.

How is LL-37 stored?

Unopened vials are stored at 2-8°C and stay stable for 12+ months. Once reconstituted with bacteriostatic water, the solution is kept at 2-8°C and used within 28-30 days.

Purity Guarantee

Every batch is ≥99% purity. Send us a COA from any independent test and we’ll issue store credit regardless of what it shows.