Also known as: Cathelicidin
LL-37 is a 37-amino-acid peptide and the only member of the cathelicidin antimicrobial-peptide family made by humans. Research includes extensive cell and biophysical work, mouse studies and a few small human trials.
LL-37 is established as a cationic, helix-forming peptide that binds negatively charged bacterial membranes and molecules such as LPS and lipoteichoic acid, disrupting membranes in lab studies [1][2]. Reviews also describe immune-signaling roles: attracting immune cells, inducing autophagy in macrophages and changing neutrophil behavior in mouse studies [1][2]. These signaling roles are context-dependent; in mice, repeated LL-37 injection is itself used to create a skin-inflammation model [5].
| Study | Model | Reported result | Source |
|---|---|---|---|
| Mouse wound model with MRSA [3] | Mouse Back-skin wound model in BALB/c mice inoculated with S. aureus (MRSA); LL-37 vs teicoplanin, topical and/or systemic | Combined topical plus systemic LL-37 group showed more re-epithelialization, granulation tissue, collagen organization and new vessel formation on histology | Peer-reviewed Antibiotics 2021 |
| Topical cream trial [4] | Human 25 adults, randomized 1:1, double-blind, placebo-controlled topical study, 4 weeks | Primary efficacy measure: granulation index. Published | Peer-reviewed Arch Dermatol Res 2023 |
| Skin-inflammation model [5] | Mouse Short-term vs long-term LL-37 skin-injection model in mice | Long-term model showed skin thickening, new vessel formation and both innate and adaptive immune activation | Peer-reviewed Anim Models Exp Med 2025 |
| Review of LL-37 and analogs [1] | Review Lab, cell and animal studies of LL-37 and modified fragments (KR-12, FK-16, OP-145 and others) | Summarizes membrane-disruption mechanism, LPS binding and analog designs aimed at stability and selectivity | Peer-reviewed Int J Mol Sci 2025 |
| Structure and activity review [2] | Review Biophysical, structural and functional studies of LL-37 | Summarizes structure, antimicrobial activity and immune-signaling roles to guide design of LL-37-based molecules | Peer-reviewed Biomolecules 2024 |
Human trials are listed for research context only; outcomes are reported in the linked publications. Animal and lab results do not establish effects in humans.
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