Peptide Comparison
Defensin (HBD-2)vsLL-37
Inducible human beta-defensin antimicrobial peptide (41 amino acids) that kills bacteria through membrane disruption at MIC 50 μg/mL against S. aureus, recruits dendritic cells and T cells via CCR6 receptor chemotaxis, and serves as a critical bridge between innate and adaptive immunity — upregulated up to 100-fold during infection and inflammation
Human cathelicidin-derived antimicrobial peptide (37 amino acids) that disrupts bacterial membranes at MIC 0.62 μM against S. aureus, neutralizes endotoxin (LPS) to prevent septic shock, and has reached Phase II clinical trials as Ropocamptide for wound healing — achieving 6-fold accelerated healing at 0.5 mg/mL in venous leg ulcers
At a Glance
Quick
comparison
Dose Range
Defensin (HBD-2)
10–100 μg/mL (research)
LL-37
0.5–1.6 mg/mL (topical)
Frequency
Defensin (HBD-2)
As needed
LL-37
Once daily
Administration
Defensin (HBD-2)
Topical application (research/wound care)
LL-37
Topical application (wound healing)
Cycle Length
Defensin (HBD-2)
Ongoing/indefinite
LL-37
12+ weeks
Onset Speed
Defensin (HBD-2)
Rapid (hours to days)
LL-37
Moderate (1-2 weeks)
Evidence Level
Defensin (HBD-2)
Moderate human trials (Phase 1-2)
LL-37
Moderate human trials (Phase 1-2)
Efficacy
Benefit
ratings
Germ Fighting
Immune Signaling
Wound Defense
Wound Healing
Fighting Infections
Immune Boost
Technical Data
Compound
specifications
Defensin (HBD-2)
Molecular Formula
Approximately C185H290N54O57S6 (41-amino acid peptide with 3 disulfide bonds)
Molecular Weight
~4,328 Da (mature peptide)
Half-Life
Short plasma half-life (minutes); locally stable at wound and epithelial sites due to disulfide-bonded structure; degraded by metalloproteinases in chronic wound environments
Bioavailability
Topical application provides local antimicrobial activity; three disulfide bonds confer resistance to proteolytic degradation; salt-sensitive — activity reduced above 150 mM NaCl; not intended for oral or systemic delivery
CAS Number
Not assigned (endogenous human peptide; research-grade available from multiple suppliers)
LL-37
Molecular Formula
C205H340N60O53
Molecular Weight
4,493.26 Da
Half-Life
Short systemic half-life (minutes) due to protease susceptibility; local tissue persistence at wound sites is longer due to binding to extracellular matrix components and lipid membranes
Bioavailability
Topical application achieves high local wound-bed concentrations; systemic bioavailability limited by rapid proteolytic degradation and serum protein binding; not intended for oral delivery
CAS Number
154947-66-7
Protocols
Dosing
tiers
Defensin (HBD-2)
LL-37
Applications
Best
suited for
Defensin (HBD-2)
Research into novel topical antimicrobial therapies for skin infections and chronic wounds
Defensin (HBD-2) is particularly well-suited for individuals focused on research into novel topical antimicrobial therapies for skin infections and chronic wounds. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Biomarker development for inflammatory skin disease monitoring (psoriasis, atopic dermatitis)
Defensin (HBD-2) is particularly well-suited for individuals focused on biomarker development for inflammatory skin disease monitoring (psoriasis, atopic dermatitis). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Understanding innate-adaptive immune crossover mechanisms in mucosal defense
Defensin (HBD-2) is particularly well-suited for individuals focused on understanding innate-adaptive immune crossover mechanisms in mucosal defense. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Development of antimicrobial surfaces and wound dressings incorporating defensin peptides
Defensin (HBD-2) is particularly well-suited for individuals focused on development of antimicrobial surfaces and wound dressings incorporating defensin peptides. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
LL-37
Treatment of chronic non-healing wounds including venous leg ulcers and diabetic ulcers
LL-37 is particularly well-suited for individuals focused on treatment of chronic non-healing wounds including venous leg ulcers and diabetic ulcers. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Immune defense against antibiotic-resistant bacterial infections (MRSA, Pseudomonas)
LL-37 is particularly well-suited for individuals focused on immune defense against antibiotic-resistant bacterial infections (mrsa, pseudomonas). Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Anti-biofilm strategies for chronic wound infections and medical device-associated infections
LL-37 is particularly well-suited for individuals focused on anti-biofilm strategies for chronic wound infections and medical device-associated infections. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Boosting innate immune defense in immunocompromised or aging individuals
LL-37 is particularly well-suited for individuals focused on boosting innate immune defense in immunocompromised or aging individuals. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Safety Profile
Side
effects
Defensin (HBD-2)
Common
- Local site irritation
- Transient inflammatory response
- Reduced activity in saline environments
Uncommon
- Localized allergic reaction
- Inflammatory amplification
Serious
- No serious adverse effects documented
LL-37
Common
- Local site irritation
- Transient stinging or burning
- Mild perilesional erythema
- Increased wound exudate
Uncommon
- Allergic contact reaction
Serious
- Hemolytic activity at systemic concentrations
Research Status
Safety
& evidence
Defensin (HBD-2)
Evidence Level
Moderate human trials (Phase 1-2)
FDA Status
Research compound
Safety Overview
Defensin HBD-2 is not FDA-approved and has no completed human clinical trials, with all safety data limited to in vitro mechanistic studies and animal models. Animal toxicology studies show no significant systemic toxicity or organ damage at doses exceeding therapeutic levels. However, human immunological responses to exogenously administered antimicrobial peptides are not fully characterized. Concerns exist regarding potential immune activation, cross-reactivity with self-antigens, and development of antibodies to the synthetic peptide. Bacterial resistance development to defensin-based therapeutics is theoretically possible. No human pharmacokinetics, dose-escalation studies, Phase 1 safety data, or clinical efficacy trials have been conducted.
Contraindications
- xKnown hypersensitivity to defensin peptides or formulation components
- xPregnancy and breastfeeding — insufficient safety data for exogenous defensin administration
- xActive autoimmune skin conditions where defensin overexpression may contribute to pathology (e.g., psoriasis flare)
- xCystic fibrosis patients — elevated airway NaCl concentrations inactivate HBD-2 antimicrobial activity
LL-37
Evidence Level
Moderate human trials (Phase 1-2)
FDA Status
Research compound
Safety Overview
LL-37 is an endogenous cathelicidin antimicrobial peptide naturally produced by immune cells and epithelial tissues, conferring inherent biocompatibility and low toxicity at physiological concentrations. Synthetic LL-37 shows excellent safety in in vitro immune assays and animal models with no hepatotoxicity, nephrotoxicity, or genotoxicity at relevant doses. At elevated concentrations, the cationic amphipathic structure can cause hemolysis and cell membrane damage, but therapeutic doses are far below these thresholds. Injection site reactions are minimal in research applications.
Contraindications
- xKnown hypersensitivity to cathelicidin peptides or formulation components
- xActive hemolytic conditions — LL-37 demonstrates concentration-dependent hemolytic activity
- xPregnancy and breastfeeding — insufficient reproductive safety data from clinical trials
- xSevere renal impairment — peptide clearance may be altered
Decision Guide
Which is
right for you?
Choose Defensin (HBD-2) if...
- Research into novel topical antimicrobial therapies for skin infections and chronic wounds
- Biomarker development for inflammatory skin disease monitoring (psoriasis, atopic dermatitis)
- Understanding innate-adaptive immune crossover mechanisms in mucosal defense
- Development of antimicrobial surfaces and wound dressings incorporating defensin peptides
Choose LL-37 if...
- Treatment of chronic non-healing wounds including venous leg ulcers and diabetic ulcers
- Immune defense against antibiotic-resistant bacterial infections (MRSA, Pseudomonas)
- Anti-biofilm strategies for chronic wound infections and medical device-associated infections
- Boosting innate immune defense in immunocompromised or aging individuals