Peptide Comparison
Cathelicidin (hCAP-18 / Synthetic Derivatives)vsThymalin
Human cationic antimicrobial protein-18 (hCAP-18) precursor and its synthetic derivative SAAP-148 — a next-generation 24-amino-acid cathelicidin-based peptide with broad-spectrum bactericidal activity against multidrug-resistant ESKAPE pathogens including MRSA biofilms, superior potency to its parent fragment LL-37, and retained efficacy under physiological salt and plasma conditions
Russian thymic peptide complex that rejuvenates immune function and supports healthy aging
At a Glance
Quick
comparison
Dose Range
Cathelicidin (hCAP-18 / Synthetic Derivatives)
0.5–5 mg
Thymalin
5–10 mg
Frequency
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Once daily
Thymalin
Once daily
Administration
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Topical application (primary research route)
Thymalin
Intramuscular injection
Cycle Length
Cathelicidin (hCAP-18 / Synthetic Derivatives)
4-6 weeks
Thymalin
4-6 weeks
Onset Speed
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Rapid (hours to days)
Thymalin
Moderate (1-2 weeks)
Evidence Level
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Moderate human trials (Phase 1-2)
Thymalin
Limited human trials
Efficacy
Benefit
ratings
Antibiotic-Resistant Infections
Biofilm Destruction
Immune System Support
Immune Restoration
Longevity Support
Disease Prevention
Technical Data
Compound
specifications
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Molecular Formula
hCAP-18: ~18 kDa precursor protein (170 AA); SAAP-148: C155H253N49O31 (approximate), MW 3,267.1 Da
Molecular Weight
hCAP-18 precursor: ~18,000 Da; SAAP-148: 3,267.1 Da; OP-145: ~2,900 Da
Half-Life
Plasma half-life: minutes (proteolytic degradation); local tissue persistence: hours at therapeutic concentrations in wound environment; enhanced stability compared to LL-37 due to N-terminal acetylation and C-terminal amidation
Bioavailability
Topical bioavailability optimized in hypromellose ointment formulations; SAAP-148 retains activity in human plasma unlike LL-37; systemic bioavailability limited by proteolytic degradation
CAS Number
Not assigned (SAAP-148 and OP-145 are novel synthetic derivatives)
Thymalin
Molecular Formula
Complex mixture; active dipeptide EW: C16H19N3O5
Molecular Weight
Polypeptide complex; components 250-1000 Da; active dipeptide EW ~321 Da
Half-Life
Not precisely characterized for complex; immune effects persist weeks post-administration
Bioavailability
High via intramuscular or subcutaneous injection
CAS Number
63958-90-7
Protocols
Dosing
tiers
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Thymalin
Applications
Best
suited for
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Research into next-generation antimicrobials against multidrug-resistant infections
Cathelicidin (hCAP-18 / Synthetic Derivatives) is particularly well-suited for individuals focused on research into next-generation antimicrobials against multidrug-resistant infections. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Topical antimicrobial development for wound infections with biofilm involvement
Cathelicidin (hCAP-18 / Synthetic Derivatives) is particularly well-suited for individuals focused on topical antimicrobial development for wound infections with biofilm involvement. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Understanding vitamin D-cathelicidin innate immune axis for immune optimization
Cathelicidin (hCAP-18 / Synthetic Derivatives) is particularly well-suited for individuals focused on understanding vitamin d-cathelicidin innate immune axis for immune optimization. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Development of anti-biofilm therapeutics for chronic device-related and wound infections
Cathelicidin (hCAP-18 / Synthetic Derivatives) is particularly well-suited for individuals focused on development of anti-biofilm therapeutics for chronic device-related and wound infections. Research and clinical experience suggest meaningful benefits in this area when used as part of a comprehensive treatment approach.
Thymalin
Aging Adults Seeking Immune Support
Thymalin is especially valuable for people over 55 whose thymus gland has naturally shrunk with age. By stimulating thymic function, it helps restore the immune training center that your body relies on to fight infections and stay healthy.
Longevity and Anti-Aging Protocols
Clinical studies tracking patients for 6-8 years showed Thymalin reduced mortality by 2.0-2.1-fold. Combined with Epitalon, the mortality reduction reached an impressive 4.1-fold, making this combination one of the most studied longevity peptide protocols.
Seasonal Illness Prevention
Research shows Thymalin cuts respiratory infection rates by 2.0-2.4-fold. A short 10-day course before cold and flu season can significantly boost your immune defenses for months afterward.
Safety Profile
Side
effects
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Common
- Local application site irritation
- Local inflammatory response
- Mild wound exudate increase
Uncommon
- Localized urticaria
- Transient pain at injection site
Serious
- Hemolytic activity at supratherapeutic doses
Thymalin
Common
- No side effects in most patients
- Mild injection site reaction
Uncommon
- Transient low-grade fever
- Mild flu-like symptoms
- Temporary headache
Serious
- Severe allergic reaction
Research Status
Safety
& evidence
Cathelicidin (hCAP-18 / Synthetic Derivatives)
Evidence Level
Moderate human trials (Phase 1-2)
FDA Status
Research compound
Safety Overview
Cathelicidin peptides (natural and synthetic) are not FDA-approved and have no completed human clinical trials. Animal studies demonstrate broad-spectrum antimicrobial activity without systemic toxicity at therapeutic concentrations. However, concern exists regarding immunological tolerance—cathelicidin derivatives can trigger innate immune activation and inflammatory responses at high concentrations. The peptide's mechanism on immune cells is incompletely understood in humans, and effects on chronic immune signaling, tolerance development, or off-target immune activation remain uncharacterized. Bacterial resistance development to cathelicidin-based therapeutics is theoretically possible but not yet documented clinically.
Contraindications
- xKnown hypersensitivity to cathelicidin-derived peptides or formulation components
- xPregnancy and breastfeeding — insufficient reproductive safety data for synthetic derivatives
- xActive autoimmune conditions involving cathelicidin dysregulation (e.g., rosacea, psoriasis) — exogenous cathelicidin peptides may exacerbate inflammation
- xSevere systemic immunodeficiency without medical supervision — immune modulation effects may be unpredictable
Thymalin
Evidence Level
Limited human trials
FDA Status
Research compound
Safety Overview
Thymalin has an excellent safety profile based on over 40 years of clinical use in Russia. Most patients experience zero side effects, and the peptide complex has been described as 'practically non-toxic' in research literature. It has been used safely in thousands of patients, including elderly populations over extended periods.
Contraindications
- xActive thymic tumors or malignancies
- xKnown hypersensitivity to animal-derived peptide products
- xPregnancy and breastfeeding (insufficient safety data)
- xSevere uncontrolled autoimmune disease without medical supervision
Decision Guide
Which is
right for you?
Choose Cathelicidin (hCAP-18 / Synthetic Derivatives) if...
- Research into next-generation antimicrobials against multidrug-resistant infections
- Topical antimicrobial development for wound infections with biofilm involvement
- Understanding vitamin D-cathelicidin innate immune axis for immune optimization
- Development of anti-biofilm therapeutics for chronic device-related and wound infections
Choose Thymalin if...
- Immune system restoration in aging adults
- Longevity and healthy aging support
- Reducing infection frequency and severity
- Multi-system health optimization