LL-37 vs Thymopentin (TP-5)
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
Immune-boosting pentapeptide fragment that enhances T-cell function and dendritic cell maturation
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
LL-37
1.6–1.6 mg/mL
Thymopentin (TP-5)
50–50 mg
Frequency
LL-37
Once daily
Thymopentin (TP-5)
Once daily
Administration
LL-37
Topical application (wound healing)
Thymopentin (TP-5)
Subcutaneous injection
Cycle length
LL-37
12+ weeks
Thymopentin (TP-5)
4-6 weeks
Onset speed
LL-37
Moderate (1-2 weeks)
Thymopentin (TP-5)
Moderate (1-2 weeks)
Evidence level
LL-37
Moderate human trials (Phase 1-2)
Thymopentin (TP-5)
Moderate human trials (Phase 1-2)
Benefit ratings
Wound Healing
Fighting Infections
Immune Boost
Immune Enhancement
Cardiovascular Support
Post-Recovery Support
Compound specifications
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
Thymopentin (TP-5)
Molecular formula
C30H49N9O9
Molecular weight
679.8
Half-life
30 seconds to few minutes in plasma
Bioavailability
Sustained release via subcutaneous route
CAS number
69558-55-0
Dosing compared
LL-37
Topical
0.5 mg/mL gel
Twice weekly · 4 weeks
Lowest dose in the LL-37 (ropocamptide) Phase I/IIa venous leg-ulcer trial and the most effective: ~6-fold faster healing and ~68% ulcer-area reduction vs placebo, applied to the wound twice weekly [4].
1.6 mg/mL gel
Twice weekly · 4 weeks
Mid dose in the same trial; ~3-fold improvement and ~50% area reduction vs placebo. The highest tested concentration (3.2 mg/mL) showed no benefit over placebo, so dose escalation above this is not supported [4].
Thymopentin (TP-5)
Subcutaneous injection
50 mg
Three times weekly · 6 weeks to 48 weeks depending on indication
Dose used in controlled clinical trials, e.g. 50 mg SC three times weekly in HIV and atopic dermatitis studies [5].
Intravenous injection
50 mg by slow IV
Repeated injections (e.g. three times weekly) · Several weeks
Slow intravenous infusion was used in rheumatoid arthritis trials and may enhance in-vivo potency versus bolus dosing [5].
Best suited for
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.
Thymopentin (TP-5)
Immune System Enhancement
Thymopentin directly increases T-cell function and promotes dendritic cell maturation, making it ideal for people seeking to boost immune response naturally
Cardiac Health Support
Clinical trials show thymopentin improves ejection fraction and exercise capacity in elderly heart failure patients while enhancing immune markers
Post-Surgery Recovery
Helps restore immune function after major surgery and protects important immune responses during recovery period
Side effects
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
Thymopentin (TP-5)
Common
- Local injection site reaction
- Mild fatigue
- Transient fever
Uncommon
- Muscle aches
- Mild headache
Serious
- Allergic reaction
Safety & evidence
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
- Known hypersensitivity to cathelicidin peptides or formulation components
- Active hemolytic conditions — LL-37 demonstrates concentration-dependent hemolytic activity
- Pregnancy and breastfeeding — insufficient reproductive safety data from clinical trials
- Severe renal impairment — peptide clearance may be altered
Thymopentin (TP-5)
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
Thymopentin is well-tolerated with minimal side effects reported in clinical trials. Most adverse events are mild and local. No serious safety concerns have emerged from decades of clinical use in China and Europe.
Contraindications
- Pregnancy and breastfeeding
- Active malignancy (without medical supervision)
- Severe immunosuppression
- Hypersensitivity to peptide medications
Which is right for you?
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
Choose Thymopentin (TP-5) if...
- Immune system strengthening
- Recovering from illness or surgery
- Managing autoimmune conditions
- Supporting cardiac health in elderly patients