LL-37
The only human cathelicidin antimicrobial peptide, providing broad-spectrum antimicrobial activity and immune modulation as part of the innate immune system.
Also known as: Cathelicidin, Human cathelicidin antimicrobial peptide, hCAP-18 active form
Regulatory Status
Classification date: 2024-06-01
Compounding: Not currently available for compounding
Evidence Summary
How It Works
LL-37 is a 37-amino-acid cationic peptide cleaved from the precursor protein hCAP-18. It disrupts microbial membranes through electrostatic interactions with negatively charged phospholipids, providing direct bactericidal, antiviral, and antifungal activity. Beyond direct killing, it modulates the immune response by recruiting immune cells, promoting wound healing, neutralizing bacterial endotoxins (LPS), and influencing dendritic cell and T-cell function. Its expression is upregulated by vitamin D, linking vitamin D status to innate immunity.
Common Applications
Safety & Considerations
As an endogenous human peptide, it is generally well tolerated at physiologic concentrations. High concentrations can be cytotoxic to host cells. May exacerbate inflammatory conditions such as rosacea and psoriasis (LL-37 is pathogenically elevated in these conditions). Limited human dosing data for exogenous administration. Potential for autoimmune activation. Currently not legal for compounding in the US.
Regulatory classifications can change rapidly. The information shown here was last verified on 2024-06-01. Always confirm current legal status with a licensed provider or the FDA before making treatment decisions.