Thymosin alpha-1: what the research shows
A natural immune-signaling peptide from the thymus gland, used as a medicine in some countries.
Also known as Thymalfasin, Zadaxin
At a glance
Approved as a medicine (Zadaxin) in a number of countries, mainly for hepatitis B. Not approved in the US or EU.
What is Thymosin alpha-1?
Thymosin alpha-1 is a 28-amino-acid peptide first found in the thymus, the gland behind the breastbone where some immune cells mature.
How does Thymosin alpha-1 work?
It helps switch on T cells and other parts of the immune response.
What does the research show?
- Reviews describe its use for hepatitis B and C, as an add-on to vaccines and cancer treatment, and in severe infections. The quality of the evidence varies.
Known risks and side effects
- Reviews of the human trials describe it as generally well tolerated.
- Outside an approved product, quality and strength can vary.
Is Thymosin alpha-1 approved?
Approved as a medicine in some countries, but not in the US, UK or EU.
Approved as a medicine (Zadaxin) in a number of countries, mainly for hepatitis B. Not approved in the US or EU.
From the community
Watch: Thymosin alpha-1 and related science
Start with the compound discussion, then use the background lesson to understand its biology. Each card explains its connection. Recordings may predate later findings or regulatory changes.
U.S. Food and Drug Administration
FDA compounding meeting: CJC-1295, AOD-9604 and thymosin alpha-1
The original discussion of these substances and proposed uses. Committee advice is separate from a final regulatory decision.
Official FDA recording · December 4, 2024
Official regulatory recording
Historical FDA discussion of CJC-1295, AOD-9604 and thymosin alpha-1. An advisory meeting is not approval or evidence of clinical benefit.
Khan Academy
Phagocytes and innate immunity
How part of the immune system responds to threats and contributes to inflammation.
Immune-system biology education
Related biology
Background on immune cells and inflammation for understanding Thymosin alpha-1. It does not demonstrate benefits of this compound or formulation.
National Institute of Mental Health
Different types of clinical research
An introduction to the different questions and designs used in studies involving people.
NIMH · US National Institutes of Health
Research skills
Helps you judge the study design or uncertainty in Thymosin alpha-1 research; it is not a trial of the compound.
Sources and references
- Thymosin alpha 1: a comprehensive review of the literatureDominari et al. · World Journal of Virology · 2020
- Comprehensive Review of the Safety and Efficacy of Thymosin Alpha 1 in Human Clinical TrialsDinetz et al. · Alternative Therapies in Health and Medicine · 2024
VETUD Learn explains published research in plain language. It is general information, not medical advice. Talk to a doctor before starting, stopping or changing any treatment.
In the research shop
Check the catalog for related laboratory research materials. These products are separate from the approved medicines and clinical trial formulations discussed here.
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