LL-37
Cathelicidin · CAP-18 · Human Cathelicidin Antimicrobial Peptide
Your immune system's first-line antimicrobial weapon. Now available as a standalone peptide.
Educational content only. Not medical advice. This compound may be regulated in your jurisdiction. Consult a healthcare professional.
01 What is LL-37?
LL-37 is not some obscure research chemical — it is a peptide your own body produces as part of your innate immune system. It is the only cathelicidin antimicrobial peptide found in humans, produced by white blood cells, epithelial cells, and barrier tissues when they detect pathogens. It literally punches holes in bacterial membranes. The biohacking interest stems from people with chronic infections, biofilm-related illness (like chronic Lyme disease or CIRS), or those who want to boost their innate antimicrobial defences. Since LL-37 works differently from antibiotics — through direct membrane disruption rather than metabolic inhibition — bacteria cannot easily develop resistance to it. This is one of those compounds where the science is solid (we know exactly what it does and how), but the clinical application as a standalone therapeutic is still being developed. Your body makes it; the question is whether supplementing it externally provides additional benefit.
02 How Does It Work?
LL-37 is an amphipathic alpha-helical peptide that inserts itself into bacterial cell membranes, forming pores that destroy membrane integrity. Unlike antibiotics that target specific bacterial processes, this physical membrane disruption works against a broad spectrum of bacteria, fungi, and even enveloped viruses. Beyond direct antimicrobial action, LL-37 modulates the immune response: it recruits immune cells to infection sites, neutralises endotoxin (LPS), promotes wound healing, and can disrupt bacterial biofilms. The biofilm disruption is particularly relevant for chronic infections where bacteria hide in protective extracellular matrices that antibiotics cannot penetrate.
03 What Does The Research Say?
Moderate evidence. Some human data, mostly animal studies.
Extensive basic science research confirms LL-37's antimicrobial activity against gram-positive and gram-negative bacteria, fungi, and viruses. Studies show biofilm disruption capability, wound healing promotion, and immune modulation. Clinical application research is ongoing: trials for wound healing, chronic infections, and as an adjunct to conventional antibiotics. Some research explores it for conditions like rosacea (where LL-37 dysregulation plays a role). The challenge is delivery — as a peptide, it is rapidly degraded in the body, requiring injection or targeted delivery systems.
04 Reported Dosages
Research literature dosages only. NOT medical recommendations. Always consult a healthcare professional.
No established therapeutic dose for systemic use. Community protocols: 50-200 mcg subcutaneously, daily for courses of 2-4 weeks. Some practitioners use it topically for wound healing. Often combined with other immune-supporting peptides like Thymosin Alpha-1. These are research dosages, not medical recommendations.
05 Side Effects & Risks
Injection site reactions (redness, swelling — expected given it activates innate immunity). Potential for autoimmune activation in susceptible individuals (LL-37 can act as a self-antigen in conditions like psoriasis). Mild flu-like symptoms possible as immune system activates.
06 Legal Status
Not approved for therapeutic use. Research chemical.
Not FDA-approved. Research chemical. Not scheduled.
Not approved. Research chemical.
Not approved. Research chemical.