LL-37
UnregulatedAlso known as: Cathelicidin, Human Cathelicidin Antimicrobial Peptide, hCAP-18
Immune & AntimicrobialLast reviewed: April 28, 2026
The only human cathelicidin antimicrobial peptide, LL-37 is a 37-amino-acid peptide naturally produced by immune cells, epithelial cells, and barrier tissues. It plays a critical role in innate immunity by directly killing bacteria, viruses, and fungi, while also modulating inflammatory responses. Increasingly studied for chronic infections, biofilm disruption, and immune regulation.
Mechanism of Action
Disrupts microbial membranes through electrostatic interaction with negatively charged bacterial surfaces, creating pores that kill pathogens. Also modulates immune responses by recruiting immune cells, promoting wound healing, and disrupting bacterial biofilms. Acts as a bridge between innate and adaptive immunity.
Common Uses
- Immune system support
- Chronic infection management
- Biofilm disruption (Lyme, SIBO)
- Wound healing
- Upper respiratory infection support
Known Risks
- Injection site reactions (pain, redness)
- Potential autoimmune activation at high doses
- Limited human clinical data for therapeutic use
- Overexpression linked to psoriasis and rosacea in some contexts
Regulatory Status
Not FDA-approved as a therapeutic. LL-37 is an endogenous human peptide being studied in clinical trials for wound healing and infection. Some compounding pharmacies have offered it, but it has no formal FDA category for compounding. Research is ongoing for topical wound applications.
Common Protocols
Protocol information is for educational reference only. Dosing varies significantly by individual, condition, and physician guidance. Always work with a licensed healthcare provider.
Subcutaneous injection
Typical Dose
50–100 mcg
Frequency
Daily or every other day
Cycle Length
4–8 weeks
Often used in integrative medicine protocols for chronic infections and biofilm-related conditions. Some practitioners combine with other immune peptides like thymosin alpha-1. Topical formulations also exist for wound care.
Related Compounds
Research References
Related Articles
This information is for educational purposes only and does not constitute medical advice. Always consult a qualified healthcare professional before starting any peptide therapy. Data is compiled from published research and regulatory sources and may not reflect the most recent developments.