Description
LL-37 is the only human cathelicidin and the primary antimicrobial peptide of innate immunity in humans. Structurally it is a 37-amino-acid peptide released from the precursor protein hCAP-18 after proteolytic cleavage. The name “LL-37” derives from the two N-terminal leucine residues and the total length of 37 amino acids.
The research mechanism is multilayered. The central activity lies in direct antimicrobial action against bacteria, viruses and fungi. The cationic, amphipathic structure of LL-37 allows interaction with negatively charged microbial membranes and leads to membrane permeabilization. In preclinical studies, this broad antimicrobial spectrum has been documented.
Beyond direct antimicrobial activity, LL-37 shows immune-modulatory effects in research models: leukocyte chemotaxis, modulation of cytokine production, promotion of wound healing and angiogenic properties. This multi-modality makes LL-37 a mechanistically complex but well-characterized research tool at the interface between innate immunity and repair.
In preclinical studies, LL-37 has been used in wound healing models, skin research setups and inflammation studies. A particularity: LL-37 levels are altered in some chronic inflammation states, also making the compound relevant in pathophysiological research.
LL-37 is available in 5mg vials as 10-vial packs.
This information is for research and educational purposes only. No medical recommendations.
Risks & Safety
LL-37 is described as largely well tolerated per study reports. As an endogenous antimicrobial peptide of innate immunity, the compound is mechanistically well characterized.
Observed in research and user reports:
- Injection site: mild redness or irritation at the injection site is the most common local observation, typical for subcutaneously applied peptides.
- Membrane activity: the cationic, amphipathic structure of LL-37 permeabilizes microbial membranes, and local irritation is plausible as an expression of this activity.
- Immune modulation: beyond its antimicrobial action, LL-37 modulates chemotaxis and cytokine production, an active intervention in innate immunity. Altered LL-37 levels are documented in some chronic inflammation states.
- No long-term data: the characterization comes predominantly from preclinical models, and robust long-term human data do not exist.
This classification does not replace medical advice. Risk and responsibility for any actual use lie entirely with the buyer.
Studies
- LL-37: structure and function - Biochimica et Biophysica Acta 2006: Mechanism characterization.
- Cathelicidins in innate immunity - Annual Review of Immunology 2012: Overview of the cathelicidin family.
- LL-37 in wound healing research - Peptides 2017: Repair axis and immune-modulatory pathways.
