Page data last changed: . Registry refreshes and identity assessments are separate from scientific content review.
Flagship human AMP — bridges peptide chemistry and host defense.
Also known as: cathelicidin LL-37 · hCAP18 fragment
Part of the Foundational & therapeutic peptides cluster
Overview
LL-37 is the active 37-residue peptide from human cathelicidin, a cornerstone molecule in antimicrobial peptide and innate immunity research.
Source & context
Biological / chemical source: Human cathelicidin (CAMP gene product)
Primary research or clinical context: Innate immunity and infection research; therapeutic development ongoing
Host defense biology
LL-37 exhibits antimicrobial, immunomodulatory, and wound-related activities in experimental systems. Structure–activity work explores amphipathic helices and membrane interaction.
Translation challenges
Like many AMPs, moving from promising biophysics to safe systemic drugs is hard: toxicity, stability, and cost remain active research problems.
Sequence of the selected reference form
Sequence backbone for the reference form: Native human LL-37, unmodified 37-residue mature peptide. Termini, stereochemistry and modifications are described below.
LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Residues plotted ~100° apart around an α-helix — clustering of one color reveals an amphipathic face.
Structure & chemistry
Molecular identity & reference confidence
Source-supported reference
The reviewed human mature LL-37 chain and the PubChem molecular graph agree exactly. The alternate linked CID is chemically equivalent according to independently retrieved InChIKey and stereocentre counts; differing record IDs alone do not establish different forms.
- Molecular form
- Native human LL-37, unmodified 37-residue mature peptide
- Species
- Homo sapiens
- Termini (N / C)
- Free alpha-amino group of L-leucine / Free L-serine carboxylic acid (-COOH)
Average reference mass · Molecular identity assessment: 2026-10-05
Reference policy updated: 2026-10-05
- PubChem PUG molecular properties and explicit molecular graph · 2026-10-05
- PubChem PUG stereochemistry and normalized structure identity · 2026-10-05
- Reviewed UniProt molecular sequence and processed-chain annotations · 2026-10-05
- The human gene FALL39 and processing of the cathelin precursor to the antibacterial peptide LL-37 in granulocytes. · 2026-10-05
- Molecular formula
- C205H340N60O53
- Average reference mass
- ≈ 4,493
- Backbone
- Native human LL-37, unmodified 37-residue mature peptide
- C-terminus
- Free L-serine carboxylic acid (-COOH)
- PubChem CID: 16198951
Chemistry values: curated profile, PubChem.
Clinical development snapshot
ClinicalTrials.gov lists 20 registered studies with “LL-37” as an intervention (snapshot 2026-09-06). A registry footprint is not evidence of efficacy or approval.
| NCT | Title | Phase | Status | Updated |
|---|---|---|---|---|
| NCT05054361 | Crosstalk Between Mucosal-Associated Invariant T (MAIT) Cells and the Gut Microbiota and Mucosa in the Develop | — | recruiting | 2026-04-13 |
| NCT07280754 | Evaluation of 25(OH)D3 and LL-37 Levels in Periimplant Sulcus Fluid | — | not yet recruiting | 2025-12-19 |
| NCT06867250 | Peri-implant Vitamin D and Cathelicidin (LL-37) Levels | — | completed | 2025-03-10 |
| NCT06219330 | Cathelicidin LL-37 Relation to Potentially Malignant Lesions | — | completed | 2024-01-23 |
| NCT04404335 | The Role of Anti-inflammatory Cytokines and Antimicrobial Peptide LL-37 Biomarkers in the Treatment of Periodo | — | completed | 2022-09-30 |
| NCT02225366 | Intratumoral Injections of LL37 for Melanoma | Phase 2 | completed | 2021-12-09 |
LL-37 — reconstitution calculator
Enter how much peptide is in the vial and how much diluent (e.g. bacteriostatic water) is added. The tool returns the resulting solution concentration — and, for any amount you type, the volume it corresponds to. This is educational arithmetic, not a dosing recommendation.
Reference form: Native human LL-37, unmodified 37-residue mature peptideAverage reference mass: 4,493 Da
Enter an amount to see the volume it corresponds to.
Educational concentration mathematics only. This tool does not recommend a dose, amount, or protocol, and nothing here is medical advice. Many peptides are not authorized by Health Canada for human use — see our reconstitution and bacteriostatic-water guides for context.
FAQ about LL-37
What is LL-37?+
LL-37 is the active 37-residue peptide from human cathelicidin, a cornerstone molecule in antimicrobial peptide and innate immunity research.
What Canadian product status is recorded for LL-37?+
Canadian product status for LL-37 has not been verified in this profile. No verified record here does not mean no authorization exists. Status depends on the product, formulation and use; consult Health Canada's product records.
What is the length of the selected reference form for LL-37?+
The selected reference form (Native human LL-37, unmodified 37-residue mature peptide) has 37 residues or residue-derived units in its backbone. Other forms in this family may have a different length.
Related peptides
References & further reading
- 1.Bucki et al. (2010). Cathelicidin LL-37: a multitask antimicrobial peptide. Arch Immunol Ther Exp (Warsz)
- 2.Golec (2007). Cathelicidin LL-37: LPS-neutralizing, pleiotropic peptide. Ann Agric Environ Med
- 3.Suzuki et al. (2022). Human Cathelicidin Peptide LL-37 Induces Cell Death in Autophagy-Dysfunctional Endothelial Cells. J Immunol
- 4.Voronko et al. (2025). Antimicrobial Peptides of the Cathelicidin Family: Focus on LL-37 and Its Modifications. Int J Mol Sci
- 5.Lee et al. (2020). Cathelicidin LL-37 (an antimicrobial peptide)-induced colistin dependence in Acinetobacter baumannii. Diagn Microbiol Infect Dis
- 6.Wang et al. (2019). Design of Antimicrobial Peptides: Progress Made with Human Cathelicidin LL-37. Adv Exp Med Biol
- 7.Segreto et al. (2024). Cathelicidin LL-37 Expression in Human Breast Implant Capsules. Plast Reconstr Surg
- 8.Memariani et al. (2023). Antibiofilm properties of cathelicidin LL-37: an in-depth review. World J Microbiol Biotechnol
- 9.PubChem — compound summary for LL-37 (CID 16198951)
- 10.Wikipedia — Cathelicidin antimicrobial peptide