What Is LL-37?

Also known as: Cathelicidin

LL-37 is the only cathelicidin-class antimicrobial peptide humans produce — a 37-amino-acid molecule that is part of the innate immune system's front line. It punctures bacterial membranes directly and, unusually, also disrupts biofilms, the protective slime layers that make chronic infections stubborn.

Research interest spans chronic infections (Lyme-adjacent protocols, sinusitis, gut dysbiosis) and immune modulation. It is a double-edged molecule: both antimicrobial hero and, when overexpressed, a driver of autoimmune skin conditions like psoriasis and rosacea — which is why dosing conservatism matters.

What is LL-37 studied for?

Side effects & safety

The most reported of any peptide on this site relative to its usage: injection-site inflammation is common, and its role in psoriasis/rosacea biology means flares of inflammatory skin conditions are a real risk. Keep doses low and short.

Legal & approval status

Research chemical; no human approvals. Handle as the most 'active' immune molecule in the catalog.

Typical dosing at a glance

Commonly reported protocols use 50 mcg–100 mcg, daily, via subcutaneous injection. For the mixing math — how much bacteriostatic water, exact syringe units, doses per vial — see the LL-37 reconstitution calculator →

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Educational overview based on published research and commonly reported community protocols — not medical advice, and not an endorsement of any compound. Consult a licensed healthcare provider.