What it is
Thymosin alpha-1 is a peptide first found in the thymus gland, which helps train immune cells. The drug version is called thymalfasin.
It appears to help activate certain immune cells, especially T cells, and is studied for infections and as an add-on to vaccines and cancer care.
US regulatory status
Not FDA-approved in the US. It is approved (as Zadaxin) in a number of other countries, mainly for hepatitis B and C and immune support; it is not an accepted bulk substance for US compounding.
What the research shows
Clinical studies, many from outside the US, suggest possible benefits as an add-on treatment for hepatitis B and in some immune-weakened patients. Results have been mixed, and it did not earn US approval.
How it is given
Subcutaneous injection (approved outside the US)
Commonly reported side effects
- Injection site discomfort or redness
- Joint or muscle aches
- Tiredness
- Limited data in healthy people
Questions to ask your provider
- What does the research really show about thymosin alpha-1 in humans?
- Are there FDA-approved treatments for my goal that have stronger evidence?
- What are the risks of products labeled "research use only," and how would I know what is really in them?
Informational only. We are not doctors. PepSteady does not give medical advice, diagnose, or recommend doses, and we do not sell peptides. Always follow your licensed healthcare provider and pharmacist.