What Is LL-37? Antimicrobial Peptide Research Guide
An overview of LL-37 — the human cathelicidin peptide — covering how it is studied in antimicrobial and immune research, and its research-use-only status in the UK.
7 min read · Published 2026-06-23
What Is LL-37?
LL-37 is a 37-amino-acid peptide and the only known human cathelicidin antimicrobial peptide. It is a component of the innate immune system and is studied for both its antimicrobial and immunomodulatory roles.
Research use only. This material is supplied for in-vitro laboratory research. It is not a medicine and is not for human or veterinary consumption, administration, or therapeutic use.
How LL-37 Is Studied to Work
In research LL-37 is associated with direct antimicrobial activity against bacteria and with modulation of immune and wound-healing processes. Its biology is complex — studies note both protective and, in some contexts, pro-inflammatory roles — which is itself a subject of investigation.
Evidence & Regulatory Status
LL-37 research spans antimicrobial, immunology and dermatology models, largely preclinical. LL-37 is not approved as a medicine by the MHRA and is supplied for laboratory research only.
Research Handling & Quality
As a lyophilised (freeze-dried) peptide it is typically stored frozen and reconstituted with bacteriostatic water for in-vitro work — see our reconstitution guide and storage guide. Identity and purity should be verified against a batch-matched Certificate of Analysis (COA) with HPLC and mass-spectrometry data. View ll-37 product details and COA.
Frequently Asked Questions
Is LL-37 approved in the UK?
No. LL-37 is supplied for laboratory research use only and has no UK marketing authorisation.
What is LL-37 studied for?
It is examined for antimicrobial activity and for its roles in innate immunity and wound healing in laboratory models.
Is LL-37 naturally occurring?
Yes — it is the human cathelicidin peptide produced by the innate immune system; research-grade LL-37 is synthesised for laboratory study.
Related Guides
- What Is KPV? Anti-Inflammatory Tripeptide Research Guide
- What Is BPC-157? Research, Mechanisms & Where to Buy in the UK
- What Is a Certificate of Analysis (COA)? How to Read One
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