LL-37 (Cathelicidin)

What is LL-37 (Cathelicidin)?

LL-37 (Cathelicidin) is the only antimicrobial peptide the human body makes from the cathelicidin family, and that single fact explains both its appeal and its risks. It is a short, charged 37-residue helix cut from a precursor protein and switched on by vitamin D, infection, inflammation, and wounding. In one molecule it kills microbes, breaks up biofilms, mops up bacterial toxins, calls in immune cells, and helps wounds close. That breadth is real and genuinely impressive, and it is backed by a large mechanistic literature spanning antimicrobial, immune, and wound-repair biology.

From the BioHarmony report, reviewed 2026-09-08.

How it is thought to work

Pore-forming membrane disruption of microbes, biofilm breakdown, LPS neutralization, immune-cell chemotaxis, wound re-epithelialization, and angiogenesis

Safety watch-outs

• Any personal or family history of psoriasis, lupus, or rheumatoid arthritis: do not use systemically
• LL-37 is a confirmed autoimmune trigger and autoantigen.
• Any active, prior, or suspected cancer: avoid
• LL-37 is a documented growth factor for several tumor types.
• A new or worsening skin flare, rash, or scaly plaque after starting: stop immediately, since this can reflect the psoriasis-linked…

Full risk profile in the BioHarmony report.

Dosing as published

No approved-label or study protocol is recorded for LL-37 (Cathelicidin) yet.

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