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LL-37

Human Cathelicidin | Antimicrobial & Immune Support

LL-37 is the only human cathelicidin antimicrobial peptide, a 37-amino acid cationic peptide derived from hCAP18 that exhibits broad-spectrum antimicrobial activity against bacteria, viruses, and fungi while modulating immune responses and promoting wound healing.

Daily dose

0.5-1.6 mg/mL topical

Frequency

Daily to twice weekly

Cycle length

2-8 weeks

Storage

2-8°C

Key benefits

Direct wound healing acceleration, local antimicrobial protection, enhanced tissue regeneration

How it works

Topical application provides direct access to wound sites, promoting keratinocyte migration, angiogenesis, and antimicrobial protection without systemic exposure

Dosage protocols

Goal

Chronic Venous Ulcers

Dose

0.5 mg/mL · Twice weekly

Route

Topical gel application

Goal

Diabetic Foot Ulcers

Dose

0.5-1.6 mg/mL · Daily application

Route

Topical cream

Goal

Acute Wound Healing

Dose

1.6 mg/mL · Once daily

Route

Topical gel or cream

Goal

Pressure Ulcer Treatment

Dose

0.5-1.0 mg/mL · Twice daily

Route

Hydrogel delivery system

Goal

Burn Wound Care

Dose

1.0 mg/mL · Once to twice daily

Route

Topical gel application

Research indications

wound Healing

Chronic Venous Leg UlcersClinical trials show 68% ulcer area reduction with 0.5 mg/mL concentration
Diabetic Foot UlcersEnhanced granulation tissue formation and healing rate in clinical studies
Pressure UlcersChitosan hydrogel delivery systems demonstrate accelerated healing in animal models

immunity

Local Antimicrobial ProtectionBroad-spectrum activity against wound pathogens including antibiotic-resistant bacteria
Biofilm DisruptionEffective against established bacterial biofilms in chronic wounds
Infection PreventionReduces bacterial colonization and prevents wound infection progression

skin Health

Epithelial Cell ProliferationStimulates keratinocyte migration and proliferation for faster wound closure
Angiogenesis PromotionEnhances VEGF production and new blood vessel formation
Collagen SynthesisSupports proper extracellular matrix formation and tissue strength

Administration

injectable
topical

Interactions

Synergistic
BPC-157Enhanced wound healing and tissue repair through complementary mechanisms - LL-37 provides antimicrobial protection while BPC-157 accelerates tissue regeneration.
Synergistic
TB-500Combined anti-inflammatory and healing effects with LL-37 providing antimicrobial activity and TB-500 enhancing cellular migration and angiogenesis.
Synergistic
Conventional AntibioticsLL-37 demonstrates synergistic effects with chloramphenicol, ciprofloxacin, and oxacillin against multidrug-resistant bacteria, with FICI values 0.25-0.5.
Synergistic
Vitamin D3Vitamin D3 acts as cofactor for VDR to induce endogenous LL-37 production, enhancing innate immune responses and antimicrobial activity.
Compatible
LactoferrinBoth antimicrobial peptides can be used together safely with no documented negative interactions in wound healing applications.
Use Caution
Physiological Salt SolutionsHigh salt concentrations in physiological environments can reduce LL-37 antimicrobial activity. Consider dosing adjustments in high-salt conditions.
Avoid Combination
Amino Acid SolutionsPhysical incompatibility may occur with certain amino acid solutions, particularly in IV formulations. Avoid co-administration in same solution.
Unknown
Novel Synthetic AMPsLimited data on interactions with other synthetic antimicrobial peptides. Clinical interaction profile not established for most combinations.

Safety notes

Use only on clean, debrided wounds as directed by healthcare provider

Monitor for signs of wound infection or delayed healing

Discontinue if signs of hypersensitivity or allergic reactions develop

Use sterile technique for application to prevent contamination

Research studies

MRSA Biofilm Eradication Study (2019)

In vitro | 10-100 μM | 60 minutes | >4 log reduction in biofilm

CDC biofilm reactor study showing LL-37 achieved superior antimicrobial efficacy against Staphylococcus aureus biofilms compared to conventional antibiotics and silver nanoparticles.

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Multidrug-Resistant Bacteria Study (2017)

Clinical isolates | 1-256 μg/mL MIC | Various pathogens | Broad-spectrum activity

Comprehensive antimicrobial profile study against human pathogens including antibiotic-resistant strains, demonstrating broad-spectrum activity and potential as alternative to conventional antibiotics.

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Venous Leg Ulcer Clinical Trial (2014)

Humans | 0.5-3.2 mg/mL topical | 4 weeks | 68% ulcer area reduction at 0.5 mg/mL

First-in-man randomized, placebo-controlled trial in 34 participants with hard-to-heal venous leg ulcers. Demonstrated significant wound healing improvement with 6-fold higher healing rate constants for optimal doses.

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Structural Analysis in Lipid Micelles (2008)

NMR spectroscopy | Molecular structure | Amphipathic helix characterization

High-resolution NMR study determining three-dimensional structure of LL-37 in SDS micelles, revealing curved amphipathic helix-bend-helix motif critical for antimicrobial activity.

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Melanoma Phase I Clinical Trial (NCT02225366)

Humans | Intratumoral injection | 8 weeks | Safety and immune stimulation

Phase I dose-escalation study evaluating intratumoral LL-37 injections in melanoma patients with cutaneous metastases, demonstrating safety and potential immune system stimulation.

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Diabetic Foot Ulcer Clinical Trial (NCT04098562)

Humans | LL-37 cream | 28 days | Enhanced granulation tissue formation

Randomized controlled trial evaluating LL-37 cream in diabetic foot ulcers with mild infection, showing enhanced healing rate and granulation index improvement.

View study →