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For research and educational purposes only. Not intended for human consumption.

LL-37

Well Researched
Updated Dec 2025

Human Cathelicidin | Antimicrobial & Immune Support

InjectableTopical
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0.5-1.6 mg/mL
Twice weekly to daily
Injectable
Topical: Clean wound surface
2-8 weeks
Typical duration
2-8°C
Refrigerated

Overview

What is LL-37?

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.

Key Benefits

Direct wound healing acceleration, local antimicrobial protection, enhanced tissue regeneration, biofilm disruption.

Mechanism of Action

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

Molecular Information

4,493 Da
Weight
37
amino acids
Cationic antimicrobial peptide
Type
Amino Acid Sequence:
Leu-Leu-Gly-Asp-Phe-Phe-Arg-Lys-Ser-Lys-Glu-Lys-Ile-Gly-Lys-Glu-Phe-Lys-Arg-Ile-Val-Gln-Arg-Ile-Lys-Asp-Phe-Leu-Arg-Asn-Leu-Val-Pro-Arg-Thr-Glu-Ser
* Only human cathelicidin antimicrobial peptide derived from hCAP18

Pharmacokinetics

Peak
30 min
Half-life
30 min
Cleared
~2.5 hrs
100%50%0%0h6h12h18h24h
Peak
Half-life
Cleared
Limited human data

Research Indications

Chronic Venous Leg Ulcers

Clinical trials show 68% ulcer area reduction with 0.5 mg/mL concentration.

Diabetic Foot Ulcers

Enhanced granulation tissue formation and healing rate in clinical studies.

Pressure Ulcers

Chitosan hydrogel delivery systems demonstrate accelerated healing in animal models.

Research Protocols

Disclaimer: LL-37 is primarily used topically for wound healing. These protocols are based on clinical research. Consult a healthcare provider before use.

GoalDoseFrequencyRoute
Chronic Venous Ulcers0.5 mg/mLTwice weeklyTopical gel application
Diabetic Foot Ulcers0.5-1.6 mg/mLDaily applicationTopical cream
Acute Wound Healing1.6 mg/mLOnce dailyTopical gel or cream
Pressure Ulcer Treatment0.5-1.0 mg/mLTwice dailyHydrogel delivery system
Burn Wound Care1.0 mg/mLOnce to twice dailyTopical gel application

Timing: Apply after wound cleaning. Can be used with standard dressings. Monitor wound healing progress.

Peptide Interactions

How to Reconstitute

Important: Always use bacteriostatic water (BAC). Sterile technique is essential.

1

Ensure wound area is properly cleaned and debrided if necessary

2

Apply thin layer of LL-37 gel or cream directly to wound surface

3

Cover with appropriate sterile dressing if recommended

4

Change dressing according to clinical protocol (typically daily to twice weekly)

5

Monitor wound healing progress and adjust application frequency as needed

6

Document wound measurements and healing progression

Dosing Calculator

Calculate your injection volume with visual dosing guide

FINAL CONCENTRATION
2.50mg/mL
Each milliliter contains 2.50 mg of peptide
VISUAL REFERENCE (RESEARCH USE ONLY)

To obtain 250 mcg from this solution:

Draw 0.10 mL=10 units

(1 mL = 100 units on any insulin syringe)

0102030405060708090100
00.10.20.30.40.50.60.70.80.91.0
0.10 mL
10 units

Draw to this mark for 250 mcg

This calculator is for research purposes only. Always verify calculations and consult protocols.

Quality Indicators

Sterile Formulation

Topical LL-37 should be sterile with preservatives appropriate for wound care.

Appropriate Gel Base

Compatible gel or cream base that doesn't interfere with peptide activity.

Proper Concentration

Clinical-grade concentrations (0.5-1.6 mg/mL) with verified potency.

Cold Storage Maintenance

Maintained at 2-8°C throughout storage and transport.

Contaminated Products

Any signs of microbial contamination or non-sterile preparation.

Improper pH Formulation

pH outside physiological range that could irritate wound tissue.

What to Expect

  • Week 1-2: Reduced bacterial load, initial wound bed preparation
  • Week 2-4: Increased granulation tissue formation, epithelial migration
  • Week 4-6: Significant wound size reduction, improved healing quality
  • Week 6-8: Continued healing progress toward complete wound closure

Side Effects & Safety

Side Effects

  • 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

When to Stop

  • Signs of allergic reaction
  • Worsening wound infection
  • Severe skin irritation
  • As directed by physician
  • Upon wound closure

References

3 Studies

MRSA Biofilm Eradication (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.

Venous Leg Ulcer Clinical Trial (2014)

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

First-in-man randomized, placebo-controlled trial in 34 participants with hard-to-heal venous leg ulcers. Demonstrated significant wound healing improvement.

View Study

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.

Quick Start Guide

Typical Dose
0.5-1.6 mg/mL
How Often
Daily to twice weekly based on wound type
Where to Inject
Topical: Clean wound surface
Timing
Apply after wound cleaning, can be used with standard dressings
Effects Timeline
Initial response: 1-2 weeks; Significant healing: 4-6 weeks
Storage
Refrigerate 2-8°C, protect from light, use within expiration
Cycle Length
2-8 weeks depending on wound healing progress
Break Between
Continue until complete healing achieved

Research Disclaimer

LL-37 is sold for laboratory research purposes only and is not intended for human or animal consumption. The information provided on this page is compiled from published research, veterinary studies, and anecdotal reports for educational purposes. This content does not constitute medical advice, diagnosis, or treatment recommendations. Any research involving LL-37 must comply with all applicable local, state, and federal regulations. BioInfinity Lab makes no claims regarding the safety or efficacy of LL-37 for any purpose. Consult qualified professionals for any research applications.