Thymosin Alpha-1
Immunomodulatory peptide naturally produced by the thymus. Approved as a medication in more than 30 countries (not in the US) for hepatitis B and C, immunodeficiencies, and as a vaccine adjuvant. One of the peptides with the most clinical evidence outside of GLP-1.
Last updated:: 06/04/2026
Research Status
ANVISA (Brazil)
Not regulated
FDA (USA)
Compounding only
EMA (Europe)
Not regulated
Mechanism of Action
Thymosin alpha-1 modulates the immune system by stimulating T cell maturation, natural killer (NK) cell activity, and cytokine production. It also stimulates dendritic cells and macrophages, improving both innate and adaptive immunity.
Study Protocols
Dosages and regimens used in published clinical studies. This does not constitute a medical prescription.
Imunomodulação / hepatite B crônica
Subcutânea (SC)Aprovado em mais de 35 países para hepatite B. Aumenta atividade de células NK e T. Marca comercial: Zadaxin.
Benefits
Chronic hepatitis B treatment
ProvenApproved in over 30 countries for hepatitis B. Meta-analyses confirm efficacy in viral suppression and seroconversion.
View studyImmunomodulation
ProvenDocumented stimulation of T cells, NK cells, and adaptive immune response across multiple clinical studies.
Vaccine adjuvant
Under researchClinical studies show enhanced immune response when administered alongside vaccines, especially in immunocompromised patients.
Risks and Side Effects
Injection site pain
Low(Common)Most reported side effect. Generally mild and transient.
Internet vs. Science
What people say online compared to the actual scientific evidence.
Prevents all immune diseases
Partially trueWhat they claim
Promoted as a 'super boost' for the immune system that prevents everything.
Actual evidence
It is a proven immunomodulator, but does not prevent all diseases. Primary efficacy is in hepatitis and as an adjuvant. It is not a universal 'cure' for immune problems.
| Claim | O que dizem | Evidência real | Verdict |
|---|---|---|---|
| Prevents all immune diseases | Promoted as a 'super boost' for the immune system that prevents everything. | It is a proven immunomodulator, but does not prevent all diseases. Primary efficacy is in hepatitis and as an adjuvant. It is not a universal 'cure' for immune problems. | Partially true |
Studies and References (1)
Andreone P, Cursaro C, Gramenzi A, et al. — Expert Opinion on Pharmacotherapy (2008)
Revisão demonstrando eficácia da thymosin alpha-1 na hepatite B crônica, com taxas de soroconversão superiores ao interferon em alguns estudos.
PubMedFrequently Asked Questions
Why isn't it approved in the US/Brazil?
Zadaxin (thymosin alpha-1) is approved in over 30 countries, but SciClone Pharmaceuticals did not complete the FDA approval process. In Brazil, there is no ANVISA registration. In Feb/2026, the FDA reclassified it to Category 1, allowing compounding by pharmacies.
Important notice
This content is strictly informational and educational, based on published scientific research. It does not constitute medical advice, prescription, or encouragement to use any substance. Always consult a qualified physician before starting any treatment.
How to Obtain
This compound can be prepared by licensed compounding pharmacies with a valid prescription. Consult a physician first.