Lentinan vs Thymalin
Mushroom-derived β-glucan polysaccharide with potent immunomodulatory and antitumor properties approved for cancer therapy in Japan
Russian thymic peptide complex that rejuvenates immune function and supports healthy aging
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Quick comparison
Dose range
Lentinan
2–2 mg
Thymalin
5–10 mg
Frequency
Lentinan
Once weekly
Thymalin
Once daily
Administration
Lentinan
Intravenous infusion
Thymalin
Intramuscular injection
Cycle length
Lentinan
8-12 weeks
Thymalin
4-6 weeks
Onset speed
Lentinan
Moderate (1-2 weeks)
Thymalin
Moderate (1-2 weeks)
Evidence level
Lentinan
Moderate human trials (Phase 1-2)
Thymalin
Limited human trials
Benefit ratings
Immune
Healing & Recovery
Anti-Aging
Immune Restoration
Longevity Support
Disease Prevention
Compound specifications
Lentinan
Molecular formula
(C6H10O5)n (repeating glucose units)
Molecular weight
~500,000 g/mol (varies by preparation)
Half-life
Approximately 15-30 minutes (IV administration)
Bioavailability
100% (intravenous administration)
CAS number
37339-90-5
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
Dosing compared
Lentinan
Intravenous
1 mg per dose
Twice weekly · Continued alongside chemotherapy cycles
Established clinical regimen in Japan (approved 1985 as a biological response modifier for gastric cancer): 1 mg IV twice weekly combined with chemotherapy such as tegafur or 5-FU [1][6].
2 mg per dose
Once weekly (some protocols every 2-3 weeks) · Continued alongside chemotherapy cycles
Alternative approved IV schedule: 2 mg once weekly; more recent protocols give 2 mg every 2-3 weeks. Used as an immunomodulatory adjunct to S-1/tegafur-based chemotherapy in advanced/recurrent gastric cancer [1][6].
Thymalin
Intramuscular injection
5-10 mg reconstituted in saline
Once daily · 5-10 day course, often repeated every 6 months
Reflects the Russian clinical course used in immune-restoration and gerontology protocols, typically 10 mg IM daily for 5-10 days [1].
Subcutaneous injection
10 mg
Once daily · Up to 20 day course, repeated every 6 months
Subcutaneous administration is used in community practice at the same 10 mg daily dosing; longer 20-day courses are described for cyclical immune support [1].
Best suited for
Lentinan
Advanced Gastric Cancer
Lentinan's primary and best-studied indication is as an adjuvant to chemotherapy for unresectable and recurrent gastric cancer. A multi-institutional randomized trial demonstrated significantly extended survival (297 vs 199 days median) and dramatically improved one-year survival rates (49.1% vs 0%) [1].
Lung Cancer Adjuvant Therapy
A 12-year review of clinical studies in China demonstrated that lentinan combined with chemotherapy improves outcomes in lung cancer patients, [9] with a meta-analysis confirming increased chemotherapy efficacy and improved quality of life [10].
Cancer Patients Needing Quality of Life Support
Clinical trials consistently show lentinan improves patient quality of life during cancer treatment, particularly appetite and sleep quality, while reducing the toxic side effects of chemotherapy and enabling treatment continuity [1][10].
Immunocompromised Patients
Phase 1/2 clinical trials in HIV-positive patients have explored lentinan's ability to enhance immune function when combined with antiretroviral therapy, though this application remains investigational [7][8].
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.
Side effects
Lentinan
Common
- Fever and chills
- Infusion site discomfort
- Transient fatigue
- Nausea
Uncommon
- Chest tightness or back pain
- Granulocytopenia
Serious
- Anaphylaxis
- Severe allergic reaction / Anaphylaxis
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
Safety & evidence
Lentinan
Evidence level
Moderate human trials (Phase 1-2)
FDA status
Research compound
Safety overview
Lentinan is a beta-1,3-glucan polysaccharide (not a true peptide) extracted from shiitake mushroom with a 40-year safety record in Japanese and Asian oncology practice. Parenteral lentinan shows excellent tolerability as an immune adjuvant [7] with minimal systemic toxicity—hepatotoxicity and nephrotoxicity are essentially absent in clinical use. Fever and localized reactions at injection sites (5-15% of patients) are the documented side effects. The compound works through pattern recognition receptors (Dectin-1, TLR-2) to enhance NK cell and macrophage function without inducing autoimmunity [2].
Contraindications
- Known hypersensitivity to lentinan or shiitake mushroom components
- History of anaphylactic reactions to β-glucan polysaccharides
- Severe immunosuppression where immune activation is contraindicated
- Active autoimmune disease in flare (immune stimulation could worsen)
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
- Active thymic tumors or malignancies
- Known hypersensitivity to animal-derived peptide products
- Pregnancy and breastfeeding (insufficient safety data)
- Severe uncontrolled autoimmune disease without medical supervision
Which is right for you?
Choose Lentinan if...
- Adjunctive cancer therapy (especially gastric cancer)
- Immune system enhancement during chemotherapy
- Improving quality of life for cancer patients
- Supporting immune function in immunocompromised individuals
Choose Thymalin if...
- Immune system restoration in aging adults
- Longevity and healthy aging support
- Reducing infection frequency and severity
- Multi-system health optimization