LL-37
Cathelicidin Antimicrobial Peptide LL-37
Your body's frontline antimicrobial peptide
LL-37 is the only cathelicidin antimicrobial peptide in humans. It kills bacteria, viruses, and fungi on contact and modulates the immune response.
Admin routes
Subcutaneous
Popularity
Medium
Side effects
Generally mild
AU vendors
0 rated
✓Key benefits
📈What to expect
Immune system activation; mild flu-like symptoms possible
Antimicrobial effects; biofilm disruption begins
Chronic infection markers may improve
Sustained immune modulation; reassess and cycle
Based on community reports and published research. Individual results vary significantly.
💊Dosing protocols
Immune support
100–200 mcg
Once daily
4–6 weeks
Infection/biofilm protocol
200 mcg
Once daily
4–8 weeks
Dosing information is sourced from published research and community protocols. This is not a recommendation. Consult a healthcare professional.
Research status|Extensive preclinical data - limited human clinical trials
Overview
LL-37 is a 37-amino-acid peptide and the only cathelicidin antimicrobial peptide expressed in humans. It is produced by immune cells (neutrophils, macrophages), epithelial cells, and is present in sweat, saliva, and breast milk. Beyond direct antimicrobial activity, LL-37 modulates the immune system - promoting wound healing, angiogenesis, and inflammatory regulation. It has gained interest for chronic infections, biofilm disruption, and immune support.
⚙️How it works
LL-37 kills microorganisms by disrupting their cell membranes - it inserts into bacterial lipid bilayers, forming pores that lyse the cell. It is effective against gram-positive and gram-negative bacteria, fungi, and enveloped viruses. Beyond direct killing, it recruits immune cells, promotes angiogenesis, neutralises bacterial endotoxins (LPS), and disrupts biofilms - structured bacterial communities that are resistant to antibiotics.
⚡Side effects
📅Research history
LL-37 identified as the sole human cathelicidin
Antimicrobial and immunomodulatory properties extensively characterised
Biofilm disruption activity demonstrated
Growing interest for chronic infection and Lyme disease protocols
Studied during COVID-19 pandemic for antiviral properties
Biofilm disruption
Biofilms are structured communities of bacteria that encase themselves in a protective matrix. They are responsible for chronic infections (sinusitis, Lyme co-infections, UTIs, implant infections) and are 100–1000x more resistant to antibiotics. LL-37 penetrates and disrupts biofilm structures, making the bacteria within vulnerable to the immune system and antibiotics. This is one of LL-37's most clinically relevant properties.
References
- [1]Vandamme D, et al. 'A summary of LL-37, the factotum human cathelicidin peptide.' Cellular Immunology, 2012.
- [2]Overhage J, et al. 'Human host defense peptide LL-37 prevents bacterial biofilm formation.' Infection and Immunity, 2008.
Frequently asked questions
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Open CalculatorDisclaimer: This guide is for educational and informational purposes only. It is not medical advice. The dosing protocols listed are sourced from published research and community reports and do not constitute a recommendation. Always consult a qualified healthcare professional before using any peptide. Australian regulations classify many peptides as Schedule 4 (prescription-only) substances. Check current TGA guidelines before purchasing.