Immune & Anti-Inflammatory
LL-37
cathelicidin · human antimicrobial peptide
What it is
LL-37 is the only member of the cathelicidin family of antimicrobial peptides found in humans. It's a 37-amino-acid peptide produced by neutrophils and many other cell types as a key part of the innate immune system. Has direct kill activity against bacteria, viruses, and fungi.
How it works
Disrupts microbial membranes by inserting itself and creating pores, killing the pathogen directly. Also has immunomodulatory effects: enhances macrophage activity, neutralizes endotoxin (LPS), and supports wound healing. Vitamin D upregulates LL-37 expression naturally — one reason adequate vitamin D matters for immunity.
Benefits
- Direct antimicrobial activity against drug-resistant pathogens
- Lyme disease support (anecdotal; some clinical use)
- Chronic infection support
- Wound healing
- Anti-inflammatory effects
Timeline
- Week 1–2
- Possible Herxheimer reaction (die-off symptoms).
- Week 4–8
- Reduction in chronic infection symptoms.
Dosing & titration
Standard dose100–500 mcg subQ daily
Cycle length2–4 weeks; longer for chronic conditions
When to titrate upStart very low to assess Herxheimer reaction. Increase as tolerated.
Side effects & risks
- Herxheimer (die-off) reactions: flu-like symptoms in first days/weeks
- Injection site reactions
- Rare: allergic reactions
- Pro-inflammatory effects at higher doses
Start low. Die-off symptoms can be intense if you have a significant pathogen load.
Typical price
$120–$220/moFrom a 503A compounding pharmacy.
Studies
- Vandamme D et al. A comprehensive summary of LL-37, the factotum human cathelicidin peptide — Comprehensive review. PubMedCellular Immunology, 2012
- Search PubMed for LL-37 — PubMed searchLive PubMed search
Educational reference only. Not medical advice.