Lentinan vs Thymosin Alpha-1
Mushroom-derived β-glucan polysaccharide with potent immunomodulatory and antitumor properties approved for cancer therapy in Japan
Your immune system's master trainer—a naturally occurring thymus peptide that wakes up tired immune cells, helps your body fight infections, and keeps your defenses sharp as you age.
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
Thymosin Alpha-1
1.6–1.6 mg
Frequency
Lentinan
Once weekly
Thymosin Alpha-1
Twice weekly
Administration
Lentinan
Intravenous infusion
Thymosin Alpha-1
Subcutaneous injection
Cycle length
Lentinan
8-12 weeks
Thymosin Alpha-1
8-12 weeks
Onset speed
Lentinan
Moderate (1-2 weeks)
Thymosin Alpha-1
Moderate (1-2 weeks)
Evidence level
Lentinan
Moderate human trials (Phase 1-2)
Thymosin Alpha-1
Moderate human trials (Phase 1-2)
Benefit ratings
Immune
Healing & Recovery
Anti-Aging
Immune Activation
Infection Fighting
Immune Balance
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
Thymosin Alpha-1
Molecular formula
C129H215N33O55
Molecular weight
3108.32 g/mol
Half-life
Approximately 2 hours
Bioavailability
High when injected subcutaneously (rapid absorption, peak at ~2 hours)
CAS number
62304-98-7
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].
Thymosin Alpha-1
Subcutaneous injection
1.6 mg
Twice weekly (3-4 days apart) · 6-12 months
Established clinical dose for thymalfasin (Zadaxin); body-surface-scaled as 900 mcg/m2 [4][6]. Phase III chronic hepatitis B trials used 1.6 mg SC twice weekly for 6-12 months [4].
1.6 mg daily, then 1.6 mg twice weekly
Daily for an initial loading period, then twice weekly · 12+ weeks
Some immune-adjuvant and acute protocols front-load with daily dosing before settling to the standard twice-weekly schedule [4][6].
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].
Thymosin Alpha-1
Chronic Hepatitis B or C Support
Thymosin Alpha-1 has its strongest clinical evidence here. Multiple trials show it helps clear viral loads and normalize liver enzymes, especially when combined with antiviral medications. It's approved in over 30 countries specifically for hepatitis treatment.
Cancer Treatment Support
When used alongside chemotherapy, Thymosin Alpha-1 may help maintain immune function that chemo tends to suppress. Research in lung cancer, melanoma, and liver cancer shows improved outcomes when added to standard treatments. It helps your immune system keep fighting even during tough treatments.
Age-Related Immune Decline
As you age, your thymus shrinks and produces less thymosin naturally—a process called immunosenescence. Supplementing with Thymosin Alpha-1 may help compensate, keeping your immune defenses more youthful and responsive. Think of it as replacing what your body makes less of over time.
Severe Infection Recovery
In sepsis and critical infections, Thymosin Alpha-1 has shown promise for reducing mortality by helping restore immune balance. It's particularly interesting because it modulates immunity rather than just boosting it—calming overreaction while enhancing pathogen-fighting ability.
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
Thymosin Alpha-1
Common
- Injection site reactions
- Mild fatigue
- Flu-like symptoms
Uncommon
- Mild fever
- Lymph node awareness
Serious
- 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)
Thymosin Alpha-1
Evidence level
Moderate human trials (Phase 1-2)
FDA status
FDA approved for other use
Safety overview
Thymosin Alpha-1 has one of the most extensive safety records of any peptide, with decades of clinical use across multiple countries. Studies consistently report minimal side effects—mostly limited to mild injection site reactions. The 2-hour half-life means it doesn't accumulate in your system. It's been used safely in thousands of patients with hepatitis, cancer, and other serious conditions.
Contraindications
- Organ transplant recipients on immunosuppressants
- Active autoimmune disease flares
- Known allergy to thymosin peptides
- Pregnancy or breastfeeding
- Children under 18 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 Thymosin Alpha-1 if...
- Immune system strengthening
- Chronic infection support
- Cancer adjunct therapy
- Healthy aging immune support