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Immunity8 cited studies

Thymosin Alpha-1

Immune-modulating peptide approved in 30+ countries for hepatitis and immune support.

Also known as: Thymosin Ī±1 Ā· TĪ±1
SummaryMechanismDosingSafetyStudies
Research use only ā€” not for human consumption.

What it is

Thymosin Alpha-1 (TĪ±1) is a 28-amino-acid peptide produced by the thymus gland and the active ingredient in Zadaxin. It is approved internationally for chronic hepatitis B and C and used adjunctively in immunocompromised states, sepsis, and as an oncology supportive therapy.

Mechanism of action

Enhances T-cell maturation, shifts immune response toward Th1 (cellular immunity), increases natural killer cell activity, and modulates dendritic cell function. Particularly active in immunocompromised or senescent immune systems.

Evidence summary

Approved for hepatitis B/C in 30+ countries. Significant body of clinical research in sepsis, immune reconstitution, COVID-19 adjunct, and cancer adjuvant therapy.

Typical dosing protocols

Typical dose
1600ā€“3200 mcg
Frequency
2x per week
Cycle length
8 weeks
  • 1.6 mg subcutaneous 2Ɨ per week (standard)
  • Higher doses (3.2 mg) in immune-challenged states
  • 8ā€“12 week cycles, repeat based on immune markers

Side effects & safety

  • Excellent safety profile across clinical use
  • Mild injection-site reactions most common
  • Rare flu-like symptoms in first few doses

Cited studies

  1. (1996). A randomized controlled trial of thymosin-alpha1 versus interferon alfa treatment in patients with hepatitis B e antigen antibody-and hepatitis B virus DNA-positive chronic hepatitis B. Hepatology.
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  2. (1999). Thymosin alpha1 treatment of chronic hepatitis B: results of a phase III multicentre, randomized, double-blind and placebo-controlled study. Journal of Viral Hepatitis.
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  3. (2013). The efficacy of thymosin alpha 1 for severe sepsis (ETASS): a multicenter, single-blind, randomized and controlled trial. Critical Care.
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  4. Liu F, Wang HM, Wang T, Zhang YM, Zhu X (2015). The efficacy of thymosin Ī±1 as immunomodulatory treatment for sepsis: a systematic review of randomized controlled trials. BMC Infectious Diseases.
    PMID 26715538Read source ā†—
  5. Costantini C, Bellet MM, Pariano M, et al. (2019). A reappraisal of thymosin Alpha1 in cancer therapy. Frontiers in Oncology.
    PMID 31799197Read source ā†—
  6. (2022). A Double-blind Multicenter Two-arm Randomized Placebo-controlled Phase-III Clinical Study to Evaluate the Effectiveness and Safety of Thymosin Ī±1 as an Add-on Treatment to Existing Standard of Care Treatment in Moderate-to-severe COVID-19 Patients. Indian Journal of Critical Care Medicine.
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  7. (2025). The efficacy and safety of thymosin Ī±1 for sepsis (TESTS): multicentre, double-blinded, randomised, placebo-controlled, phase 3 trial. BMJ.
    Read source ā†—
  8. (2025). Efficacy of thymosin Ī±1 for sepsis: a systematic review and meta-analysis of randomized controlled trials. Frontiers in Cellular and Infection Microbiology.
    Read source ā†—
Disclaimer

All content is for research and educational purposes. Peptides described are sold for laboratory research use only and are not intended to diagnose, treat, cure, or prevent any disease. Always consult a qualified healthcare professional before beginning any protocol.