LL-37 5 mg – Human cathelicidin, antimicrobial and immunomodulatory research peptide

What is LL-37 (5 mg)?

LL-37 is the only human cathelicidin — a cationic antimicrobial and host-defense peptide (AMP), a key element of innate immunity. It stands out for its triple profile: antibacterial/antiviral, anti-biofilm and immunomodulatory action. Additionally, in research models it supports wound healing (granulation, angiogenesis, re-epithelialization).

LL-37 is the active form of the cathelicidin peptide (CAMP) in humans. In the Peptology catalog it is assigned to the category peptides for skin, sleep and libido — in the skin and regeneration segment. It is, however, a unique immunological-antimicrobial peptide in the catalog, whose mechanism differs from purely regenerative peptides like GHK-Cu.

It is a research compound — it is not a medicinal product and holds no authorization for clinical use. LL-37 has been studied clinically in topical formulations (including RCTs on venous and diabetic foot ulcers), but the product offered by Peptology is a research-grade reagent, not intended for the treatment of wounds or infections.

In the version offered by Peptology, LL-37 is available in a 5 mg vial as a lyophilized peptide with purity ≥ 99%, confirmed by independent laboratory analysis (CoA for every batch). The product is intended exclusively for scientific research and in vitro applications.

Variant: LL-37 5 mg

This page concerns one dosage variant — LL-37 5 mg. Each vial contains 5 mg of the lyophilized peptide. A typical working reconstitution is 1 mL → 5 mg/mL. In AMP research, attention is paid to the selection of appropriate concentrations and carriers (cream/hydrogel/dressing), because antimicrobial peptides can be cytotoxic at high topical concentrations.

LL-37 is offered in the 5 mg variant. If you are researching skin regeneration by a different route, check the copper peptide GHK-Cu or the anti-aging Epitalon.

How LL-37 works — the triple mechanism

In the research literature, LL-37 is described as a peptide with an exceptionally broad action. Below are the three most frequently studied pillars.

Why LL-37 combines defense with healing

LL-37 is an innate immunity peptide that simultaneously combats pathogens and supports tissue repair. In preclinical models and clinical studies it stimulates granulation, angiogenesis and re-epithelialization — hence the interest in it in the context of hard-to-heal wounds. This makes it different from purely regenerative peptides: GHK-Cu builds collagen, while LL-37 additionally disinfects and modulates immunity.

It should be remembered that, as an AMP at high topical concentrations, LL-37 can be cytotoxic — which is why studies use selected carriers and concentrations. This data comes from the research literature and does not constitute a claim about the effect of the research-grade product offered by Peptology.

Pharmacokinetics and pharmacodynamics (research framework)

LL-37 is a cationic antimicrobial peptide with complex, multidirectional action. The most important research characteristics:

• Class: human cathelicidin (antimicrobial / host-defense peptide, AMP)
• Targets: bacterial membranes, LPS/LTA, TLR receptors, immune cells
• Three pillars: antimicrobial, anti-biofilm, immunomodulatory
• Healing: supports granulation, angiogenesis and re-epithelialization (models and topical RCTs)
• Research form: most often topical formulations (cream/hydrogel/dressing) with a selected concentration
• Caution: cytotoxicity at high topical concentrations (a feature of the AMP class)

Comparison: LL-37 vs GHK-Cu vs Epitalon

Within the same category (skin/regeneration), it is worth comparing LL-37 with two other peptides — the regenerative GHK-Cu and the anti-aging Epitalon. LL-37 stands out for its unique antimicrobial and immunological profile.

LL-37 is the only antimicrobial/immunological peptide in this group — it combines defense against pathogens with healing. GHK-Cu is responsible for collagen and skin structure, and Epitalon for cellular aging. The comparison is indicative in nature and does not constitute a recommendation for use.

Research data on LL-37

LL-37 is one of the few research peptides with data from clinical trials (topical formulations). Below are the most important directions — with the caveat that they concern the molecule, not the research-grade product.

Healing of hard-to-heal wounds

In RCTs on venous ulcers (phase IIb, HEAL LL-37) and diabetic foot ulcers (a double-blind study, ClinicalTrials.gov NCT04098562), topical LL-37 accelerated healing relative to placebo, with a good local tolerability profile.

Antimicrobial and anti-biofilm action

LL-37 shows a broad spectrum of action (Gram-positive and Gram-negative bacteria, some viruses/fungi) and inhibits the adhesion and maturation of the biofilm of key pathogens (S. aureus, P. aeruginosa, S. epidermidis).

Immunomodulation

Beyond its direct action on pathogens, LL-37 modulates the immune response — it affects TLR signaling, the formation of NET networks and the release of antimicrobial ectosomes from neutrophils. This is an area of active research; there are no publicly confirmed phase III authorizations.

Note: The information is presented for scientific and informational purposes and is based on the literature on cathelicidins. It does not constitute medical advice, a recommendation for use or a claim about the effect of the research-grade product offered by Peptology.

LL-37 profile at a glance

• The only human cathelicidin — an innate immunity peptide (AMP)
• Triple profile: antimicrobial + anti-biofilm + immunomodulatory
• Supports wound healing — granulation, angiogenesis, re-epithelialization (topical RCTs)
• Unique in the catalog — different from the regenerative GHK-Cu or the reparative BPC-157/TB-500
• Caution: AMP cytotoxicity at high topical concentrations — carrier/concentration selection
• Every batch with a CoA and purity ≥ 99%

All information provided refers to the research literature on LL-37 and should not be interpreted as a promise of effect, an instruction for use or a claim about the effect of the research-grade product offered by Peptology.

Research dosing protocols

In studies, LL-37 was most often used in topical formulations after reconstitution of the lyophilizate:

• Working reconstitution: 1 mL → 5 mg/mL (preferably with Peptide Matrix Water™); calculate precise volumes in the peptide calculator
• In wound research, topical forms (cream/hydrogel/dressing) with a selected concentration were used
• Concentration selection is key — high topical AMP concentrations can be cytotoxic
• Maximum 3 mL of solvent per vial

In research protocols on skin regeneration, LL-37 is sometimes considered alongside peptides such as GHK-Cu or BPC-157. These schedules come from the research literature and do not constitute a recommendation for self-administration.

Side effects and safety

In research on topical formulations, LL-37 is described as well tolerated. Side effects are usually mild, local and transient. The data concern research on the molecule.

Mild local reactions are most frequently reported. As an antimicrobial peptide, LL-37 can be cytotoxic at high topical concentrations — which is why the selection of carrier and concentration is key. This information is scientific in nature and does not constitute an instruction for use.

Storage and reconstitution

LL-37 is supplied as a lyophilized (freeze-dried) powder in a vial. In lyophilized form it is stable at room temperature, protected from light and moisture — refrigeration before reconstitution is not mandatory. After reconstitution, stability depends on the solvent used, with Peptide Matrix Water™ significantly extending the peptide's lifespan.

• Before reconstitution: room temperature, in the original packaging, protected from light and moisture. A refrigerator is not mandatory.
• After reconstitution with Peptide Matrix Water™: stability in the refrigerator +2 °C to +8 °C for up to 60 days under appropriate laboratory conditions — the stabilizing formula extends the peptide's lifespan relative to standard solvents.
• After reconstitution with bacteriostatic or sterile water: stability in the refrigerator +2 °C to +8 °C for up to 28 days under appropriate conditions. Do not refreeze the reconstituted solution.
• Reconstitution: in a laboratory setting, Peptide Matrix Water™, bacteriostatic water or sterile water for injection is usually used, depending on the protocol.
• Volume: maximum 3 mL of solvent (capacity of a standard vial). For a precise calculation of volume and units, use the peptide calculator.
• Homogenization: add the solvent slowly down the vial wall, without vigorous shaking, then wait 10–15 min. Swirl gently, do not shake.

Laboratory tip: With your order, you can add Peptide Matrix Water™ to the cart — a stabilizing solution designed for working with reconstituted research peptides. More in the article Bacteriostatic water vs acetic acid vs matrix water.

Frequently asked questions about LL-37

Is LL-37 exclusively antimicrobial?

No. Beyond its direct antibacterial action, LL-37 modulates the immune response (TLR, NET networks, ectosomes) and supports wound healing (granulation, angiogenesis, re-epithelialization). This is its triple profile.

Is there data on hard-to-heal ulcers?

Yes — RCTs on venous and diabetic foot ulcers showed accelerated healing with the use of topical LL-37 formulations, with good tolerability. This is data on the molecule, not on the research-grade product.

Does it act against biofilm?

Yes — inhibition of the adhesion and maturation of the biofilm of key pathogens (S. aureus, S. epidermidis, P. aeruginosa) was recorded. This is one of the main reasons for interest in LL-37 in wound research.

How does LL-37 differ from GHK-Cu?

Both are studied in the context of skin and healing, but by different routes: GHK-Cu builds collagen and remodels the skin, while LL-37 additionally combats pathogens and modulates immunity. LL-37 is an immunological peptide, GHK-Cu — a regenerative one.

Where to buy LL-37 for research?

Peptology offers LL-37 (5 mg) as a research peptide with confirmed purity ≥ 99% and independent laboratory analysis for every batch. Fast shipping, discreet packaging and certificates of purity with the product. For scientific background, also see the article Peptides — what they are, how they work, main categories and safety profile.

Related products in the Peptology catalog

Researchers working with LL-37 often also consider skin regeneration and tissue repair peptides. Each of the products below has a certificate of purity (CoA):

See the full catalog: Peptides for skin, sleep and libido · Peptides for immunity and hormonal balance · Peptides for energy and regeneration · All peptides · Blog on peptide research

Molecule identity

Laboratory reconstitution

Laboratory protocol — reconstitution, research protocols, storage

Standardized protocol applicable to all research peptides in the Peptology catalogue. To calculate the solution concentration (mg/mL) for each vial, use the peptide reconstitution calculator.

60-second protocol

Quick reference

What you need

Five rules for reconstitution

Calculating concentration

Storage

Four mistakes to avoid

Shipping information

🚚 Shipping information

• Products in our warehouse – orders placed by 15:00 on working days are dispatched the same day, later orders on the next working day.

• Delivery with GLS to your address in 3–5 working days.

• Shipping costs €5 and is free from €50.

Frequently Asked Questions (FAQ)

Is LL-37 purely antimicrobial?

No. In addition to direct antibacterial activity, LL-37 modulates the immune response (TLR, NETs, ectosomes) and supports healing.

Is there evidence for difficult-to-heal ulcers?

Yes. Randomized controlled trials (RCTs) in venous ulcers and diabetic foot ulcers show accelerated healing with topical formulations of LL-37.

Does it act against biofilms?

Yes – reported inhibition of adhesion and maturation of biofilms of S. aureus, S. epidermidis, P. aeruginosa.

Where can I buy LL-37 in Europe and what does it cost?

You can buy LL-37 in Europe online from Peptology, from 60,00 €. Delivery with GLS in 3–5 working days. Shipping is free from 50,00 €. Payment by card. Purity 99%+, with an HPLC report for every batch.

Laboratory Analysis

LL-37 - 5mg - Batch - 0226 - Purity