Cellular Research
LL-37 — Research Peptide
Cathelicidin-derived 37-amino-acid antimicrobial peptide studied for its interactions with bacterial membranes, immune-cell signaling and epithelial cell signaling in preclinical models.
$69.99 · 5mg
Third-party tested · Freedom Diagnostics
View COA · Third-party COA (Freedom Diagnostics)
- Ships from within the U.S.
- Pay by card, Apple Pay, Venmo, Cash App or crypto
- Stored frozen at −10 °F until ship day
- Batch ID and QR code on the label
For in-vitro laboratory research use only. Not for human consumption.
Specifications
LL-37 at a glance.
- Size
- 5mg
- Form
- Lyophilized powder
- Storage
- −20°C (Protected from light and moisture)
- Purity
- 99.70% (HPLC-UV · Freedom Diagnostics COA)
- Molecular weight
- 4,493.33 g/mol
- Molecular formula
- C₂₀₅H₃₄₀N₆₀O₅₃
- Certificate of Analysis
- Third-party tested (Freedom Diagnostics)
- Category
- Cellular Research
- Sequence
- LLGDFFRKSKEKIGKEFKRIVQRIKDFLRNLVPRTES
Third-party COA (Freedom Diagnostics)
Documented by a third-party lab.
Issued by Freedom Diagnostics Testing, an independent lab, with Excalibur Peptides as the client. Its lot field records the vial's cap colour (Clear Cap/Green Crimp), not a batch number. The PDF here is the same report the lab hosts.
Independent verification
Verify on Freedom Diagnostics.
This LL-37 Certificate of Analysis is hosted on Freedom Diagnostics Testing's own site. Search the code below on the lab's lookup page, or open the lab-hosted PDF. Values are shown as printed on the certificate.
Search code: Exca2606090421
- Lab
- Freedom Diagnostics Testing
- Lot
- Clear Cap/Green Crimp
- Sample
- LL-37 5mg
- Received
- 06/09/2026
- Reported
- 06/12/2026
- Purity (HPLC-UV)
- 99.70%
- Identity (LC-MS)
- Confirmed
- Net content
- 5.81 mg
View lab-hosted COA (PDF on coas.freedomdiagnosticstesting.com)
What's in the box
One vial, part by part.
5mg of LL-37, supplied as a lyophilized powder in a sealed glass vial.
On the label
Clearly labeled.
Printed label
Product name, size and a research-use-only statement.
Batch ID
A batch number is printed on every label.
QR code
Printed on the label, next to the batch ID.
Research-use line
“For research and laboratory use only — not for human consumption” runs along the bottom of the label.
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Research
Research background.
Chemical identity, proposed mechanism and published preclinical literature, for laboratory reference.
Mechanism of action
LL-37 is the only human cathelicidin-derived antimicrobial peptide, a 37-amino-acid amphipathic α-helical peptide cleaved from the hCAP18 precursor. Published research has examined its electrostatic interactions with microbial membranes, its signaling through formyl peptide receptor-like 1 (FPRL1/FPR2), and its chemotactic activity toward immune cells in preclinical models.
Research observations
- Membrane interactions with gram-positive and gram-negative bacteria characterized in vitro
- FPRL1/FPR2 receptor signaling examined in published cell studies
- Chemotactic activity toward neutrophils, monocytes and T cells examined in preclinical studies
- Epithelial cell signaling examined in published in-vitro research
- Amphipathic α-helical structure characterized by circular dichroism and NMR
Key research & publications
- Dürr et al. (2006) — Review of LL-37 structure, function and membrane-interaction mechanisms across model systems.
- Vandamme et al. (2012) — Review of LL-37 receptor interactions and immune-cell signaling in preclinical models.
- Ramos et al. (2011) — Examined LL-37 signaling in cultured epithelial cells.
Further reading
A longer overview of published LL-37 cathelicidin literature, in our research guide.
Frequently asked questions.
What is LL-37?
LL-37 is the 37-amino-acid human cathelicidin-derived antimicrobial peptide, an amphipathic α-helical peptide cleaved from the hCAP18 precursor. Published research has examined its interactions with microbial membranes and its signaling through the formyl peptide receptor FPR2.
Where can I buy LL-37 for research?
Excalibur Peptides sells LL-37 on this page as a 5mg vial of lyophilized powder, for in-vitro laboratory research only. Orders ship from Austin, Texas, to addresses within the United States, and the product's third-party Certificate of Analysis is published in our COA database. Buyers must be 21 or older and confirm research-use-only status at checkout.
How is LL-37 tested, and where is its COA?
LL-37 is third-party tested by Freedom Diagnostics Testing: purity by HPLC and identity by LC-MS. The Certificate of Analysis is published in our COA database, and the report can be looked up on the lab's own site with search code Exca2606090421.
How should LL-37 be stored in the lab?
Keep lyophilized LL-37 sealed at −20 °C, protected from light and moisture, as listed on this page. Let the vial reach room temperature before opening so moisture does not condense on the powder, and avoid repeated freeze–thaw cycles.
How fast does LL-37 ship?
LL-37 ships from Austin, Texas. Orders placed before 2 PM EST on a business day ship the same day, and delivery within the United States typically takes 2–4 business days. A tracking number is emailed when the order ships.
What payment methods can I use to buy LL-37?
We accept credit and debit cards, Apple Pay, Venmo, Cash App and cryptocurrency. Prices are in U.S. dollars.
Is LL-37 approved by the FDA?
No. The LL-37 supplied by Excalibur Peptides is not approved by the FDA for human or veterinary use. It is sold only for in-vitro laboratory research and identification purposes and is not for human consumption.
For research and laboratory use only. Not for human consumption.
All products sold on this website are intended for in-vitro laboratory research and identification purposes only. They are not for human or veterinary use and are not for human consumption.
All information is provided for educational and research purposes. Excalibur Peptides does not condone or promote the use of any product for any purpose other than legitimate scientific research and compound identification.