What LL-37 is
LL-37 is a 37-amino-acid peptide produced from the human cathelicidin precursor hCAP-18. It is part of innate immunity and has antimicrobial and immune-signaling activity in laboratory systems. A peptide being naturally present in the body does not make an injected or compounded LL-37 product proven, equivalent, or safe.
The human trial did not establish overall benefit
A phase IIb double-blind randomized trial studied topical LL-37 with compression therapy in 148 people with hard-to-heal venous leg ulcers. In the full study population, neither LL-37 concentration significantly improved healing versus placebo.[1] Exploratory or subgroup observations cannot replace that prespecified overall result, and this topical wound study does not support injected use, infection treatment, systemic immune claims, or general skin rejuvenation.
Immune activity can also create risk
LL-37 can interact with microbial membranes and host immune pathways, but its effects depend on tissue, concentration, and disease context. Human mechanistic work showed that LL-37 can bind self-DNA and activate plasmacytoid dendritic cells in psoriasis biology.[2] It is therefore inaccurate to describe LL-37 as simply antimicrobial or anti-inflammatory.
FDA identifies unresolved safety concerns
FDA states that it lacks sufficient safety information to know whether compounded cathelicidin LL-37 would harm humans and cites nonclinical findings involving male reproduction and possible tumor-promoting effects in some tissues.[3] There is no FDA-approved adverse-reaction table, validated systemic dose, or established long-term safety profile. Compounded drugs are not FDA-approved or premarket-verified for safety, effectiveness, or quality.[4]
Regulatory status
LL-37 has no FDA-approved therapeutic product or indication. The narrow topical trial remains investigational and does not validate online research vials or compounded injections. Teloryx does not publish an LL-37 dose, cycle, stack, or reconstitution recipe.