Educational guide
LL-37 Overview, Dosing & Safety | Peptide Database
LL-37 (Human Cathelicidin) Human Cathelicidin | Antimicrobial Peptide Community Research Join others researching LL-37 — share findings, ask questions, and learn from real experiences LL-37 is the only human cathelicidin antimicrobial peptide, a 37-amino acid
This guide cannot diagnose a condition or recommend a personal treatment plan. Discuss medical questions with a qualified professional.
LL-37 (Human Cathelicidin)
Human Cathelicidin | Antimicrobial Peptide
Community Research
Join others researching LL-37 — share findings, ask questions, and learn from real experiences
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.
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.
Molecular Data
Research Indications
68% ulcer area reduction demonstrated with 0.5mg/mL concentration in clinical trials.
Enhanced granulation tissue formation and wound closure.
Accelerated healing demonstrated in animal models.
Boosts natural immune defenses against pathogens.
Active against MRSA and multi-drug resistant bacteria with >4 log reduction in biofilms.
Balances immune responses without causing immunosuppression.
Stimulates skin cell growth and regeneration.
Promotes new blood vessel formation for tissue repair.
Supports collagen production for wound healing.
Dosing Protocols
Topical application is the most established route, providing direct access to wound sites with minimal systemic exposure.
Wound healing - Standard
0.5mg/mL gel/cream
Daily to twice weekly
Direct wound application
Wound healing - Intensive
1.6mg/mL gel/cream
Daily
Reconstitution Instructions
1 Clean and debride wound area
2 Apply thin layer directly to wound surface
3 Cover with sterile dressing if needed
4 Change per clinical protocol (daily to twice weekly)
5 Monitor healing progress and adjust frequency
6 Document wound measurements and progression
Interactions
What to Expect
Side Effects & Safety
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
Quality Checklist
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
Frequently Asked Questions
How much faster does LL-37 heal wounds compared to standard care?
LL-37 at 0.5mg/mL concentration reduced chronic venous leg ulcer area by 68% in clinical trials. Healing acceleration is most dramatic in weeks 2-4, with granulation tissue formation and epithelial migration visibly increasing compared to untreated wounds.
Is LL-37 effective against antibiotic-resistant bacteria?
Yes. LL-37 showed >4 log reduction in MRSA biofilms compared to conventional antibiotics. Its broad-spectrum antimicrobial activity works through membrane disruption, bypassing resistance mechanisms. It's effective against resistant gram-positive and gram-negative bacteria.
Can LL-37 be combined with antibiotics?
Yes, synergistically. LL-37 combined with conventional antibiotics shows FICI values of 0.25-0.5, indicating synergistic antimicrobial activity. Using them together may enhance efficacy against resistant organisms.
Does topical LL-37 cause systemic effects?
No. Topical LL-37 has minimal systemic absorption when applied to wounds. Effects are localized to the wound site with direct antimicrobial and healing benefits. This makes it safe for wound-specific application without systemic side effects.
References
68% ulcer area reduction demonstrated at optimal doses in chronic venous leg ulcers.
Intratumoral LL-37 in melanoma patients demonstrated safety and immune stimulation (NCT02225366).
>4 log reduction in MRSA biofilms compared to conventional antibiotics.
NMR spectroscopy determining 3D structure of LL-37.
Related Peptides
Enhanced wound healing through complementary mechanisms.
Combined anti-inflammatory and healing effects.
Disclaimer
This information is for educational and research purposes only. Consult a healthcare professional before use.