LL-37
Also known as: cathelicidin, hCAP-18 fragment
By GLPeptideSciences Editorial Team · How we evaluate evidence · Reviewed by Dr. George S. Watson, MD, Cardiothoracic Surgeon · Updated 2026-06-02
The body's principal cathelicidin antimicrobial peptide, central to host defense and studied for antimicrobial and wound-healing roles — with a notably double-edged biology.
What it is & how it works
What it is
LL-37 is the body’s main cathelicidin — an antimicrobial host-defense peptide that’s part of innate immunity.
How it is thought to work
It can disrupt microbial membranes and also modulates immune signaling and wound healing, which is the basis for therapeutic interest.
The evidence and the caveat
The important nuance: LL-37 is genuinely double-edged. It’s protective in some contexts but has been implicated in driving inflammation and certain disease processes in others. That complexity — plus the lack of established clinical use — is a real argument against casual use.
What it's discussed & studied for
- Host defense / antimicrobial activity (preclinical)
- Wound healing and inflammation discussion
Discussion of a use is not a claim that it works or is approved.
Research status
A genuine endogenous host-defense peptide with deep basic-science literature; targeted therapeutic use is investigational and not approved.
Evidence quality
Rich basic biology, but it's a double-edged molecule — implicated in both defense and certain inflammatory/disease processes — and clinical use is unestablished.
Dosing discussion
No approved or validated human protocol exists; community use is extrapolated.
Educational summary of what is discussed in the literature and community — not a dosing recommendation or medical advice.
Safety & harm reduction
Important nuance: LL-37 is genuinely double-edged — protective in some contexts, implicated in inflammatory and disease processes in others. That complexity is a real caution against casual use.
Sourcing literacy
No approved product; research-market material is unverified.
Selected literature
FAQ
Why is LL-37 called 'double-edged'?
It's protective as an antimicrobial in some contexts, but it's also been implicated in driving inflammation and certain disease processes in others — so its biology isn't uniformly beneficial.