LL-37

This is an endogenous human peptide, so the bulk of a very large literature is basic immunology and cell biology rather than clinical work: several thousand records dominated by in-vitro antimicrobial assays, expression studies in human epithelial and immune cells, receptor and mechanism work, and observational measurement of endogenous concentrations in plasma, saliva and wound fluid. Its identity is defined by human genetics rather than by synthesis: it is the mature 37-residue form released from the pro-protein hCAP-18, the product of the CAMP gene, by extracellular cleavage. Controlled human interventional data do exist, from a Swedish commercial programme: a first-in-human randomised placebo-controlled study of a topical form in 34 participants with venous leg ulcers, followed by a phase 2b double-blind randomised placebo-controlled study in 148 participants at two concentrations against placebo alongside compression.

What is not established

In the phase 2b study the primary efficacy analysis over the full population found no significant difference from placebo. A post-hoc subgroup showed differences, and no confirmatory adequately powered study of that subgroup finding has been reported, so no controlled human result stands on the full randomised population. The FDA states it lacks sufficient safety information for the routes nominated to it and flags unresolved non-clinical signals on male reproduction and pro-tumorigenic potential.

What distinguishes LL-37

Alone in this group, LL-37 is a human gene product rather than a designed or fragment construct: the mature active form of human cathelicidin, cleaved from a pro-protein encoded by the CAMP gene, and measurable endogenously in plasma and saliva. The identity question that dogs BPC-157 therefore does not arise here, because the parent protein is fully characterised and the peptide has a defined 37-residue sequence beginning with the two leucines that give it its name. It is also the only compound in this group to carry a formal non-proprietary drug name, ropocamptide, assigned during commercial development.

Sources

1. US FDA. Certain bulk drug substances for use in compounding that may present significant safety risks, cathelicidin LL-37 entry
2. Mahlapuu M et al. Phase 2b double-blind randomised placebo-controlled study of topical LL-37 in 148 participants. Wound Repair Regen. 2021;29(6):938-950
3. Gronberg A et al. Randomised placebo-controlled clinical study of topical LL-37 in refractory venous leg ulcers. Wound Repair Regen. 2014;22(5):613-21
4. Sorensen OE et al. Human cathelicidin hCAP-18 is processed to LL-37 by extracellular cleavage with proteinase 3. Blood. 2001;97(12):3951-9
5. World Anti-Doping Agency. 2026 Prohibited List, searched in full with no occurrence of LL-37 or cathelicidin

This page describes a compound as a material and summarises published research about it. It is for general and procurement information only. It is not medical advice, not a treatment recommendation, and not guidance on use. Supplied for laboratory and research use, not for human consumption.