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LL-37
LL-37 5 mg – antimicrobial cathelicidin peptide
Peptology Ltd. · Peptides for immunity and hormonal balance
LL-37 is an antimicrobial cathelicidin peptide that Peptology supplies strictly for laboratory research, in 5 mg. You can buy LL-37 in Cyprus online from €60.00, with same-day dispatch for orders placed by 15:00. 99%+ purity, HPLC/MS certificate for every batch, so every vial comes with documented quality data. Delivery in 5–7 working days with BOX NOW, free from €50; you pay on delivery – by card through the BOX NOW payment link, before you open the locker. The product is not intended for human or veterinary use.
60,00 € · In stock
For research use only / Not a medicine
| Purity | >99% |
|---|---|
| Method | HPLC + LC/MS |
| Laboratory | Analiza Białek |
| Batch | 0226 |
Last updated: 18/10/2026
What is LL-37?
LL-37 (human cathelicidin, hCAP18 fragment) is the only antimicrobial peptide of the cathelicidin family in humans — a peptide of 37 amino acids that begins with two leucines (hence the name “LL”). It is a key molecule of innate immunity, with a dual role: direct antimicrobial action and regulation of the immune response.
It is produced by epithelial and immune cells (e.g. neutrophils) as part of the body’s “first line of defence”. It acts both as a natural “broad-spectrum antibiotic” and as an immunomodulator that directs immune cells to the site of damage.
It is studied in research in models of wound healing, biofilm, innate immunity and antimicrobial action, as well as for angiogenesis. It works in a complementary way with regenerative/immune peptides such as BPC-157 and Thymosin Alpha-1. See the range in the all peptides category.
In the Peptology version, it is supplied as a lyophilised research-grade powder with purity > 99%, in a 5 mg format. It is intended exclusively for scientific, research and in vitro applications — it is not a medicine or an antibiotic.
Available form: 5 mg
5 MG
Typical research form
High-purity lyophilised powder with a laboratory certificate for each batch.
STRUCTURE
37 amino acids
The only human cathelicidin, a fragment of hCAP18.
How LL-37 works — a dual role
MEMBRANE DISRUPTION
As an amphipathic peptide, it disrupts the membranes of bacteria (and other microbes), causing their lysis — broad-spectrum antimicrobial action.
ANTI-BIOFILM & LPS
Studied for breaking down biofilm and neutralising endotoxin (LPS), reducing the inflammatory load.
IMMUNOMODULATION
Attracts immune cells (chemotaxis), regulates inflammation and promotes healing and angiogenesis.
“Antibiotic” and “signalling molecule” in one
What is special about LL-37 is its dual character: on the one hand it directly neutralises microbes by breaking down their membranes, and on the other it acts as a “signalling molecule” that directs and regulates the immune response. This pairing makes it a unique tool in the study of innate immunity and healing.
Compared with purely regenerative peptides such as BPC-157, LL-37 adds the antimicrobial/anti-biofilm dimension. It should be noted that at excessively high concentrations it can also become pro-inflammatory — something that is studied carefully. The mechanisms come from preclinical studies.
Properties and pharmacology
- Class: antimicrobial peptide — the only human cathelicidin (37 aa)
- Origin: fragment of hCAP18, from epithelial/immune cells
- Direct action: breakdown of microbial membranes (broad spectrum)
- Studied actions: anti-biofilm, LPS neutralisation, immunomodulation, wound healing
- Dual character: antimicrobial + immunoregulatory; high doses possibly pro-inflammatory
- Status: research peptide, not approved for clinical use
LL-37 vs. BPC-157 vs. Thymosin Alpha-1
Comparison of three peptides with action in healing, immunity or antimicrobial defence. Reference data.
| LL-37 | BPC-157 | Thymosin α1 | |
|---|---|---|---|
| Category | Antimicrobial peptide | Regenerative peptide | Immunostimulant |
| Main action | Antimicrobial + immunomodulation | Repair/angiogenesis | Cell-mediated immunity |
| Against microbes | Direct (membranes/biofilm) | Indirect | Indirect (immunity) |
| Wound healing | Yes | Yes (main) | Indirect |
| Status | Research | Research (WADA-prohibited) | Research |
Sources: literature on cathelicidins/antimicrobial peptides and innate immunity.
Research
Antimicrobial action and biofilm
LL-37 is one of the most studied human antimicrobial peptides: in studies it breaks down the membranes of a broad range of microbes and inhibits or disrupts the formation of biofilm — a field of particular interest against resistant microbes.
Innate immunity and healing
Beyond its direct action, in preclinical models it attracts immune cells, regulates inflammation, neutralises endotoxin (LPS) and promotes wound healing and angiogenesis.
Data limitations
Its dual character (possibly pro-inflammatory at high concentrations) and the mostly preclinical data make research cautious. LL-37 remains a research molecule, not approved for clinical use.
Note: Scientific reference based on preclinical data. It is not medical advice or a claim for the product.
In brief — scientific profile
- The only human cathelicidin (37 aa) — a key molecule of innate immunity
- Direct antimicrobial action — breakdown of microbial membranes (broad spectrum)
- Anti-biofilm & LPS neutralisation — reduces the inflammatory load
- Immunomodulation & healing — chemotaxis, angiogenesis, repair
- 5 mg form — lyophilised powder of purity > 99%
- Research product — not approved for clinical use
Side effects and safety
The safety profile of LL-37 in humans is not fully characterised. Because of its dual character, the dose relationship is a central point of attention.
Common
- Reactions/redness at the application site
- Transient irritation
- Mild local inflammation
Less common
- Transient headache
- Local oedema
- Itching
Precautions
- Allergic reaction / hypersensitivity
- High doses possibly pro-inflammatory
- Caution in chronic inflammatory/autoimmune conditions
At excessive concentrations or in certain inflammatory contexts, LL-37 may amplify inflammation — which is why the dose is studied carefully. Scientific reference, not instructions for use.
Related peptides
BPC-157
Healing/repair peptide
Thymosin Alpha-1
Immunostimulatory thymic peptide
TB-500
Tissue repair peptide
Peptide Matrix Water™
Recommended reconstitution solvent
See: All peptides · Blog
Research warning: LL-37 is offered exclusively for scientific, research and in vitro purposes. It is not intended for human/veterinary use, or for the diagnosis, treatment or prevention of any condition, and does not constitute medical advice or an antibiotic.
Is LL-37 only antimicrobial?
No. Besides its direct antibacterial action, LL-37 regulates the immune response (TLR, NETs, exosomes) and promotes healing.
Is there data on ulcers that are slow to heal?
Yes. Randomised controlled trials (RCTs) in venous ulcers and diabetic foot ulcers show accelerated healing with topical LL-37 formulations.
Molecule identity
| CAS number | 154947-66-7 |
|---|---|
| Molecular weight | 4493 g/mol |
| Molecular formula | C205H340N60O53 |
| Class | Human cathelicidin (antimicrobial peptide) |
| Form | Lyophilised powder in a glass vial |
| Storage | Lyophilisate: 2–8 °C, dry and protected from light · after reconstitution: 2–8 °C |
Buy LL-37 in Cyprus – price
You can buy LL-37 in Cyprus online from Peptology. Prices by strength:
- LL-37: €60.00
Orders placed by 15:00 on working days ship the same day and are delivered in 5–7 working days with BOX NOW. Shipping costs €2 and is free from €50; you pay on delivery – by card through the BOX NOW payment link, before you open the locker.
LL-37 5 mg: which strength
LL-37 is available in: 5 mg.
Research protocols
Important: Reference information for research purposes — not a recommendation for use or medical advice.
In the research literature, LL-37 is studied mainly in vitro and in wound/microbe models, with attention to the dose–response relationship:
- In in vitro studies, the antimicrobial/anti-biofilm action is examined across a range of concentrations
- The dose relationship is critical: low doses are immunoregulatory, very high doses possibly pro-inflammatory
- In healing models, topical application is also studied
The schedules come from the research literature and do not constitute a recommendation for individual use.
Storage and reconstitution
Supplied as a lyophilised powder in a 5 mg vial. Lyophilised, it is stable at room temperature, away from light/moisture. For reconstitution, the recommended solvent is Peptide Matrix Water™, which significantly extends the life of the solution.
- Before reconstitution: room temperature, away from light/moisture; up to 24 months.
- With Peptide Matrix Water™ (recommended): refrigerator 2–8 °C up to 60 days — the best stability option.
- With bacteriostatic water or sterile water: refrigerator 2–8 °C up to 28 days. No re-freezing.
- Reconstitution: add the solvent slowly down the wall, without vigorous agitation.
Laboratory tip: Add Peptide Matrix Water™ to your basket — the recommended stabilising solvent for all reconstituted peptides.
Laboratory protocol — reconstitution, research protocols, storage
Standard protocol, applicable to all research peptides in the Peptology catalogue. For the concentration of the solution (mg/mL) per vial, use the peptide reconstitution calculator.
The 60-second protocol
1. SOLVENT
2. RECONSTITUTION
The solvent is added to the wall of the vial, without agitation, then wait 10–15 minutes.
3. CALCULATION
Calculator → concentration in mg/mL
4. STORAGE
+2 °C to +8 °C, up to 60 days with Peptide Matrix Water
Quick reference
| Parameter | Value |
|---|---|
| Form | Lyophilised powder |
| Solvent | Peptide Matrix Water |
| Volume for reconstitution | 1–3 mL — 3 mL maximum (capacity of the standard vial) |
| Storage before reconstitution | Room temperature, protected from direct light (refrigeration is not mandatory) |
| After reconstitution | Up to 60 days at +2 °C to +8 °C with Peptide Matrix Water |
What you will need
Precision pipette
Calibrated, 100–1000 µL — for accurate measurement of the volume of solvent added to the vial.
70% alcohol pads
Two pads — to disinfect the peptide vial and the solvent vial.
Stabilised solvent for lyophilised peptides. Why this one.
Five rules for reconstitution
| ✅ Correct | ❌ Wrong |
|---|---|
| Disinfect the stoppers and the work surface with 70% alcohol, work with gloves | Working without disinfection |
| The solvent is added slowly down the wall of the vial | Direct jet onto the powder — foaming and denaturation |
| Light swirling between the palms | Shaking — foam, on which the peptides denature |
| Wait 10–15 minutes at room temperature | Mechanical mixing or heating |
| Visual inspection: clear, without particles | Using a cloudy or coloured solution |
Calculating the concentration
⚠️ Maximum 3 mL of solvent. The standard vial does not allow a larger volume — do not exceed it during reconstitution.
- Concentration (mg/mL) = mg in the vial ÷ mL of solvent
- Volume per sample (mL) = amount per sample (mg) ÷ concentration (mg/mL)
- 1 mg/mL = 1 µg/µL · 1 mL = 1000 µL
Reconstitution per vial — solvent: Peptide Matrix Water. Concentration after addition (1 mg/mL = 1 µg/µL):
| Vial | + 1 mL | + 2 mL | + 3 mL |
|---|---|---|---|
| 5 mg | 5 mg/mL | 2.5 mg/mL | 1.67 mg/mL |
👉 For any vial and solvent volume — use the calculator. It calculates the concentration (mg/mL, µg/µL) and the volume per sample (mL, µL).
Storage
BEFORE RECONSTITUTION
Room temperature, protected from direct light, in the original packaging. Refrigeration is not mandatory.
AFTER RECONSTITUTION
+2 °C to +8 °C, up to 60 days with Peptide Matrix Water. Discard the remainder after this period.
FREEZING
Not recommended. Freeze/thaw cycles degrade the structure of the peptide.
Four mistakes to avoid
1. Shaking for “faster dissolution”
Foam = denaturation. Only gentle swirling between the palms.
2. Unsuitable solvent
For the stability of the peptide structure, use only a sterile, purpose-designed solvent — Peptide Matrix Water is recommended.
3. Ignoring slight cloudiness
If it is not completely clear = the sample does not meet the criteria for work.
4. Removing it from the refrigerator “for an hour or two”
Short exposures add up and jeopardise stability.
Research status: All Peptology products are intended exclusively for laboratory use and research. They are not pharmaceutical products, have not been approved for human or veterinary use and do not replace medical advice. The protocol described is standard laboratory practice for working with lyophilised peptides.
How is it stored?
The lyophilised vial is stored at room temperature, away from light. After reconstitution: with Peptide Matrix Water™ — up to 60 days at 2–8 °C; with bacteriostatic water — up to 28 days.
Purity and certificate of analysis
99%+ purity, HPLC/MS certificate for every batch.
LL-37 - 5mg - Batch - 0226 - Purity
Shipping and payment
Orders placed by 15:00 on working days ship the same day and are delivered in 5–7 working days with BOX NOW. Shipping costs €2 and is free from €50; you pay on delivery – by card through the BOX NOW payment link, before you open the locker.
🚚 Delivery information
- Orders placed by 15:00 are dispatched the same day, delivery in 5–7 working days.
-
Shipping with BOX NOW, chosen at checkout. Free shipping from €50, otherwise €2.
Frequently asked questions about LL-37
Where can I buy LL-37 in Cyprus and what does it cost?
In Cyprus you can buy LL-37 online from Peptology, from €60.00. Delivery in 5–7 working days with BOX NOW, free from €50; you pay on delivery – by card through the BOX NOW payment link, before you open the locker.
What is LL-37?
It is the only antimicrobial peptide of the cathelicidin family in humans (37 amino acids). It acts as a natural “broad-spectrum antibiotic” and as an immunomodulator of innate immunity.
In what form is LL-37 available?
As a lyophilised powder in a glass vial (5 mg). It is reconstituted in the laboratory with Peptide Matrix Water™ or bacteriostatic water; you can work out the concentration (mg/mL) with the <a href="/page/peptide-calculator">reconstitution calculator</a>.
Which side effects have been reported in clinical studies of LL-37?
Most often mild local reactions . At high local concentrations, AMPs may be cytotoxic - so suitable carriers and concentrations are used.
How long does delivery take and how do I pay?
Orders placed by 15:00 on working days ship the same day and are delivered in 5–7 working days with BOX NOW. Shipping costs €2 and is free from €50; you pay on delivery – by card through the BOX NOW payment link, before you open the locker.