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Over 100 clinical trials is an unusual depth of evidence for any peptide, and thymosin alpha-1 has it — spanning hepatitis B and C, cancer immunotherapy adjuvancy, and COVID-19 immune restoration. Marketed as Zadaxin and approved for medical use in China, Italy, and several other countries, it occupies a rare position: a research peptide with a genuinely international clinical footprint.
Thymosin Alpha-1: A Thymic Immunomodulatory Peptide
Thymosin Alpha-1 (Tα1) is an immunomodulatory 28-amino acid peptide naturally produced by thymic epithelial cells that has been studied in over 100 clinical trials for applications ranging from hepatitis B and C treatment to cancer immunotherapy adjuvancy and COVID-19 immune restoration. Synthesized as thymalfasin and marketed as Zadaxin® by SciClone Pharmaceuticals, it is approved for medical use in China, Italy, and several other countries, giving it an unusually deep clinical data set compared to most research peptides.
Monthly search volume for “thymosin alpha 1 price” reflects the compound’s high demand in research settings worldwide.
Mechanism of Action in Research
- TLR9 Agonism: Primary mechanism — Tα1 activates Toll-like receptor 9 (TLR9) on plasmacytoid dendritic cells, triggering type I interferon production and innate immune activation
- T-Cell Maturation: Promotes thymic differentiation of CD4+ and CD8+ T-cell precursors, the cellular basis for Tα1’s immunorestorative effects
- NK Cell Enhancement: Increases NK cell cytotoxicity against virally infected and tumor cells
- Cytokine Modulation: Upregulates IL-2, IFN-γ, IFN-α; downregulates IL-4, IL-5 — shifting from Th2 to Th1 immune dominance
- Myeloid Differentiation: Promotes monocyte-to-dendritic cell differentiation, enhancing antigen presentation capacity
Clinical Research Data
Hepatitis B (Most Extensively Studied)
- Meta-analysis of 10 randomized trials: Tα1 + interferon-α achieved HBeAg seroconversion in ~40% of patients vs. ~25% for interferon alone
- Improved HBsAg clearance rates at 12-month follow-up in multiple Phase 3 studies
- Reduced viral load rebound after treatment cessation compared to standard therapy
Cancer Immunotherapy Research
- Randomized trials in NSCLC and hepatocellular carcinoma demonstrate Tα1 as effective adjuvant to standard chemotherapy
- Improved immune recovery markers post-chemotherapy cycles (faster lymphocyte count restoration)
- Phase 2 data: Tα1 + anti-PD-1 checkpoint inhibitor combination shows synergistic tumor response rates in some solid tumors
COVID-19 Research (2020–2021)
- Multiple Chinese hospital studies (retrospective and prospective) documented faster clinical recovery in severe COVID-19 patients treated with Tα1
- Proposed mechanism: restoration of lymphopenia (the hallmark of severe COVID immunosuppression)
Dosage Reference for Research
| Context |
Dose |
Route |
Frequency |
| Clinical (approved) |
1.6 mg |
SC |
2× weekly for 6–12 months |
| In vitro immune cell studies |
1–100 ng/mL |
Culture media |
As per protocol |
| Rodent models |
40–400 µg/kg |
SC or IP |
Daily or 2–3× weekly |
HPLC Verified
Thymosin Alpha-1
Purity: 99%+ HPLC
Format: Lyophilized Powder
Testing: Third-Party COA
$170
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Frequently Asked Questions
What is thymosin alpha-1’s primary mechanism?
TLR9 agonism. It activates Toll-like receptor 9 on plasmacytoid dendritic cells, triggering type I interferon production and innate immune activation — which then cascades into T-cell maturation, NK cell enhancement, and a Th2-to-Th1 cytokine shift.
How does it differ from thymalin?
Composition, primarily. Thymosin alpha-1 is a single synthetic 28-amino acid peptide acting through TLR9; thymalin is a polypeptide mixture extracted from bovine thymus that engages multiple thymic peptide receptors. The two also emerged from different research traditions — international versus Russian geroprotective medicine.
What does the hepatitis B evidence show?
A meta-analysis of 10 randomized trials found Tα1 combined with interferon-α achieved HBeAg seroconversion in roughly 40% of patients versus about 25% for interferon alone, with improved HBsAg clearance rates at 12-month follow-up.
Summarized for scientific reference. Thymosin Alpha-1 from Core Power Peptides is for in vitro and laboratory research only — not for human consumption, and not a substitute for medical advice.
