Structure · schematic
Peptide chain of 37 amino acids · Antimikrobielles Peptid
Sequence
LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Schematic representation of the amino acid chain — not a chemical structural formula. Each node represents one amino acid (shown truncated).
Research areas*
* Contexts in which the peptide has been scientifically studied — not assured or recommended effects.
Mechanism of action
- LL-37 is the only human cathelicidin — a 37-amino-acid peptide produced by proteolytic cleavage from the precursor protein hCAP-18.
- It acts directly antimicrobially by destabilising bacterial cell membranes (cationic charge + amphipathic helical structure).
- In addition, LL-37 has immunomodulatory functions: it activates Toll-like receptors (TLR), promotes the chemotaxis of immune cells, stimulates angiogenesis via VEGFR-2 and accelerates wound healing.
- LL-37 is produced mainly in neutrophils, mast cells and epithelial cells — especially after tissue injury or infection.
Research status
- LL-37 is one of the best studied human antimicrobial peptides and the subject of active clinical research.
- Phase II studies investigated topical LL-37 formulations in chronic wounds (venous ulcers) and acne.
- In a Phase II trial in venous leg ulcers (Lipigen, 2014), improved wound healing and biofilm reduction were described.
- Further studies address the role of LL-37 deficiency in psoriasis, atopic dermatitis and pneumonia.
- Systemic use scenarios beyond wound treatment and skin conditions are not clinically established.
Evidence level
Cited studies
- 2001Human cathelicidin, hCAP-18, is processed to the antimicrobial peptide LL-37 by extracellular cleavage with proteinase 3
- 2010LL-37-induced human mast cell chemokine production is mediated by G protein-coupled receptors and toll-like receptors
- 2019Topical LL-37 (human cathelicidin antimicrobial peptide) and acne vulgaris: A randomized phase IIa study
Known risks
- 01Potentially pro-inflammatory effects at high systemic concentration
- 02Ambivalent evidence on its role in carcinogenesis: both tumour-suppressing and tumour-promoting effects described
- 03No safety data for systemic use outside clinical studies
- 04Local skin irritation possible with topical use
- 05No regulated quality standards from research-chemical sources
Frequently asked questions
What is LL-37?
LL-37 is the only human cathelicidin — a 37-amino-acid peptide produced by proteolytic cleavage from the precursor protein hCAP-18.
What type of peptide is LL-37?
LL-37 belongs to the Antimicrobial peptide class.
Is LL-37 legal in Germany?
LL-37 is not approved as a medicine in Germany. Obtaining it outside clinical studies is legally problematic.
Where can I buy LL-37?
Peptica sells nothing and names no sources. LL-37 is "not approved" in Germany; obtaining unapproved substances outside clinical studies is illegal and carries quality and safety risks.
Is LL-37 banned in sport (WADA)?
LL-37 is currently not on the WADA Prohibited List.
What are the known risks of LL-37?
Documented risks include: Potentially pro-inflammatory effects at high systemic concentration; Ambivalent evidence on its role in carcinogenesis: both tumour-suppressing and tumour-promoting effects described. This is not a complete safety assessment and not medical advice — see the risks section for the full list.
How well researched is LL-37?
The evidence is classified as “early clinical studies”. 3 studies are cited on this page.
What is the molecular weight of LL-37?
LL-37 has a molar mass of about 4493 Da.
Which peptides are related to LL-37?
Closely related entries: BPC-157, TB-500. A direct side-by-side comparison is available via the compare function.
Related entries
Legal status
Germany
not approvedAustria
not approvedSwitzerland
not approvedEU
not approvedUSA
not approvedCanada
not approvedLegal status varies by country and can change. This is not legal advice.
Sources & methodology
- 3 peer-reviewed studies cited, linked to PubMed where available.
- Molecular data verified against PubChem and primary literature. PubChem CID 16198951
- Editorial standard: no dosage guidance, no sources, evidence level stated explicitly.
Last editorially reviewed: 28 May 2026
Legal assessment
LL-37 is not an approved medicine in the EU. Clinical studies are ongoing within regulated trial programmes. Use outside controlled studies is not covered by any approval. Not on the WADA list. Importing it as a research chemical may, depending on the context, fall under the German Medicines Act (AMG).
Important notice
This site is intended solely for factual, scientifically oriented information about peptides. It does not constitute medical advice, does not replace a consultation with a doctor and contains no recommendations for use in humans.
This site does not sell any substances and names no sources for unapproved substances. For medical questions, please consult qualified medical professionals.
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