Peptide Comparison
Bestatin (Ubenimex)vsThymalin
Natural dipeptide analogue aminopeptidase inhibitor with dual immunostimulatory and antitumor activity, approved in Japan as adjuvant cancer therapy
Russian thymic peptide complex that rejuvenates immune function and supports healthy aging
At a Glance
Quick
comparison
Dose Range
Bestatin (Ubenimex)
10–100 mg
Thymalin
5–10 mg
Frequency
Bestatin (Ubenimex)
Once daily
Thymalin
Once daily
Administration
Bestatin (Ubenimex)
Oral (capsule)
Thymalin
Intramuscular injection
Cycle Length
Bestatin (Ubenimex)
12+ weeks
Thymalin
4-6 weeks
Onset Speed
Bestatin (Ubenimex)
Moderate (1-2 weeks)
Thymalin
Moderate (1-2 weeks)
Evidence Level
Bestatin (Ubenimex)
Moderate human trials (Phase 1-2)
Thymalin
Limited human trials
Efficacy
Benefit
ratings
Immune
Healing & Recovery
Anti-Aging
Immune Restoration
Longevity Support
Disease Prevention
Technical Data
Compound
specifications
Bestatin (Ubenimex)
Molecular Formula
C16H24N2O4
Molecular Weight
308.37 g/mol
Half-Life
Approximately 2-3 hours (oral administration)
Bioavailability
Well absorbed orally; peak plasma concentration reached within 1-2 hours
CAS Number
58970-76-6
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
Bestatin (Ubenimex)
Thymalin
Applications
Best
suited for
Bestatin (Ubenimex)
Adjunctive AML Immunotherapy
Bestatin is specifically approved in Japan for patients with acute non-lymphocytic leukemia who have achieved complete remission after induction chemotherapy. Clinical trials demonstrated significant prolongation of disease-free survival when bestatin was added to standard maintenance therapy.
Post-Chemotherapy Immune Recovery
By stimulating bone marrow stem cell proliferation and enhancing T-lymphocyte and macrophage function, bestatin supports immune system recovery in patients whose immune function has been suppressed by cytotoxic chemotherapy.
Pulmonary Arterial Hypertension (Investigational)
Through inhibition of LTA4 hydrolase and reduction of pro-inflammatory leukotriene B4, bestatin is being investigated as a novel approach to PAH. Eiger BioPharmaceuticals conducted Phase 2 trials (NCT02664558) and received FDA orphan drug designation for this indication.
Lymphedema Management (Investigational)
The anti-inflammatory properties of bestatin via LTB4 pathway inhibition have led to Phase 2 investigation (NCT02700529) for lymphedema, a condition with limited treatment options where inflammation plays a key role in disease progression.
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
Bestatin (Ubenimex)
Common
- Gastrointestinal discomfort
- Skin rash or pruritus
- Facial flushing
- Fatigue
Uncommon
- Elevated liver enzymes
- Mild leukopenia
Serious
- Severe allergic reaction
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
Bestatin (Ubenimex)
Evidence Level
Moderate human trials (Phase 1-2)
FDA Status
Research compound
Safety Overview
Bestatin (ubenimex) has an established safety profile based on decades of clinical use in Japan for AML maintenance therapy at 30 mg daily. The compound is generally well-tolerated, with the most common side effects being mild gastrointestinal symptoms and skin reactions. Japanese post-marketing surveillance and long-term clinical studies have not identified major safety concerns at standard doses. Phase 2 trials in the US for PAH and lymphedema also demonstrated acceptable safety profiles at higher doses.
Contraindications
- xKnown hypersensitivity to bestatin or any component of the formulation
- xPregnancy and breastfeeding (insufficient safety data)
- xSevere hepatic impairment
- xActive autoimmune diseases in flare
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 Bestatin (Ubenimex) if...
- Adjunctive immunotherapy following chemotherapy for acute leukemia
- Restoring immune function during and after cancer treatment
- Supporting bone marrow recovery post-chemotherapy
- Emerging treatment for pulmonary arterial hypertension (PAH)
Choose Thymalin if...
- Immune system restoration in aging adults
- Longevity and healthy aging support
- Reducing infection frequency and severity
- Multi-system health optimization