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LL-37

Well Studied

Human Cathelicidin | Antimicrobial Peptide

Dose 0.5-1.6 mg/mL topical gel or 100-150 mcg injectable
Frequency Topical: Daily to twice weekly on wounds. Injectable: Once daily subcutaneous
Cycle 2-8 weeks depending on wound healing progress
Storage Lyophilized: 2-8°C. Reconstituted: 2-8°C, maintain sterility

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.

Mechanism of Action

Provides direct antimicrobial activity through membrane disruption, promotes wound healing by enhancing keratinocyte migration and angiogenesis, and modulates immune responses without systemic exposure when used topically.

Key Benefits

  • Direct wound healing acceleration
  • Broad-spectrum antimicrobial activity
  • Activity against resistant bacteria (MRSA, MDRPA)
  • Enhanced tissue regeneration
  • Immune modulation
  • Local antimicrobial protection
Chain Length
37 amino acids
Type
Cationic antimicrobial peptide

Wound Healing

  • Chronic Venous Leg Ulcers

    68% ulcer area reduction demonstrated with 0.5mg/mL concentration in clinical trials.

  • Diabetic Foot Ulcers

    Enhanced granulation tissue formation and wound closure.

  • Pressure Ulcers

    Accelerated healing demonstrated in animal models.

Immunity

  • Innate Immune Enhancement

    Boosts natural immune defenses against pathogens.

  • Antimicrobial Resistance

    Active against MRSA and multi-drug resistant bacteria with >4 log reduction in biofilms.

  • Immunomodulation

    Balances immune responses without causing immunosuppression.

Skin Health

  • Epithelial Cell Proliferation

    Stimulates skin cell growth and regeneration.

  • Angiogenesis Promotion

    Promotes new blood vessel formation for tissue repair.

  • Collagen Synthesis

    Supports collagen production for wound healing.

Topical application is the most established route, providing direct access to wound sites with minimal systemic exposure.

GoalDoseFrequencyRoute
Wound healing - Standard0.5mg/mL gel/creamDaily to twice weeklyDirect wound application
Wound healing - Intensive1.6mg/mL gel/creamDailyDirect wound application

Reconstitution Instructions

  1. 1 Clean and debride wound area
  2. 2 Apply thin layer directly to wound surface
  3. 3 Cover with sterile dressing if needed
  4. 4 Change per clinical protocol (daily to twice weekly)
  5. 5 Monitor healing progress and adjust frequency
  6. 6 Document wound measurements and progression
BPC-157

Enhanced wound healing through complementary mechanisms.

synergistic
TB-500

Combined anti-inflammatory and healing effects.

synergistic
Conventional Antibiotics

FICI values 0.25-0.5 against resistant bacteria when combined.

synergistic
Vitamin D3

Acts as cofactor for endogenous LL-37 production.

synergistic
Lactoferrin

Safe combined use with no negative interactions.

compatible
Physiological Salt Solutions

High salt concentrations may reduce antimicrobial activity.

monitor
Amino Acid Solutions

Physical incompatibility, especially with IV formulations.

avoid
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

Week 6-8

Continued healing toward wound closure

Common Side Effects

  • Generally well-tolerated
  • Mild injection site reactions (injectable)
  • Local irritation at application site (topical)

Stop Signs - Discontinue if:

  • Severe injection site reactions with spreading inflammation
  • Allergic reaction signs (rash, difficulty breathing, swelling)
  • Persistent flu-like symptoms
  • Signs of wound infection (increased redness, warmth, drainage)
  • Worsening wound condition or delayed healing
  • Unusual pain or irritation at application site

Contraindications

  • Pre-existing hypersensitivity to peptides
  • Compromised immune status (relative contraindication)
  • Non-sterile wound environments

Good Signs

  • Sterile, clear formulation
  • ≥98% purity by HPLC
  • White to off-white lyophilized powder
  • Proper cold chain maintenance (2-8°C)
  • Appropriate gel base compatible with peptide activity
  • Clinical-grade concentrations (0.5-1.6mg/mL)

Warning Signs

  • Brief room temperature exposure acceptable if promptly refrigerated
  • Homemade topical formulations may lack sterility

Bad Signs

  • Discolored or cloudy solutions
  • Yellow discoloration or visible particles
  • Pre-mixed liquid formulations (LL-37 unstable long-term)
  • Non-sterile preparations
  • Microbial contamination
  • Venous Leg Ulcer Trial - Grönberg et al.
    Wound Repair and Regeneration (2014)

    68% ulcer area reduction demonstrated at optimal doses in chronic venous leg ulcers.

  • Melanoma Phase I Trial
    (2015)

    Intratumoral LL-37 in melanoma patients demonstrated safety and immune stimulation (NCT02225366).

  • MRSA Biofilm Study - Noore et al.
    PLOS ONE (2019)

    >4 log reduction in MRSA biofilms compared to conventional antibiotics.

  • Structural Analysis - Wang et al.
    Journal of Biological Chemistry (2008)

    NMR spectroscopy determining 3D structure of LL-37.

Disclaimer

This information is for educational and research purposes only. Consult a healthcare professional before use.