Is thymosin alpha-1 approved?

It is approved as Zadaxin in China and around thirty other countries but is not approved by the US FDA. The research material we supply is not that medicine and is for laboratory use only.

What has thymosin alpha-1 research looked at?

Randomised and retrospective work in severe sepsis and severe COVID-19; a large phase-3 sepsis trial was not conclusive on overall mortality. The cited studies are above.

What is thymosin alpha-1?

A 28-amino-acid immunomodulatory peptide, also called thymalfasin.

Thymosin alpha-1 research: what the studies have looked at

This page summarises the published research on thymosin alpha-1, for reference. It sets out what each study tested and in whom, not an outcome for any person, and it is not medical advice. Thymosin alpha-1 is approved as a medicine in some countries but not by the US FDA; what we supply under this name is a research chemical for laboratory use only.

What thymosin alpha-1 is

Thymosin alpha-1 (thymalfasin) is a 28-amino-acid immunomodulatory peptide. It is approved and marketed as Zadaxin in China and a number of other countries, mainly as an immune modulator and adjunct in certain infections, but it is not approved by the US FDA. The material we supply is unapproved research material, not the approved medicine, and it is not for human or animal use.

What the studies investigated

Wu et al. (2013), Critical Care 17(1):R8 (ETASS). Human, randomised, severe sepsis. Investigated thymosin alpha-1 as an add-on in severe sepsis Source.

TESTS Collaborators (2025), BMJ. Human, phase-3, sepsis (n=1106). Investigated thymosin alpha-1 in sepsis and reported no conclusive reduction in overall mortality Source.

Liu et al. (2020), Clinical Infectious Diseases. Human, retrospective, severe COVID-19. Investigated the association with outcomes in a retrospective severe-COVID cohort Source.

Mechanism, as described in the literature

The literature describes thymosin alpha-1 as a modulator of T-cell and innate immune responses, studied in randomised and retrospective work in severe sepsis and in severe COVID-19. The clinical picture is mixed and stated honestly: a large phase-3 sepsis trial did not show a conclusive reduction in overall mortality. None of that describes what a research powder does outside a supervised trial.

The material we supply

We supply thymosin alpha-1 as a research chemical, released against a written specification with a batch certificate of analysis. It is not Zadaxin or any other medicine, and it is not for human or animal use. For the vial sizes, the price per mg and how to order, see the thymosin alpha-1 compound page; the COA lookup pulls the certificate for any batch. The references above link to each study’s record; this summary is for research and educational reference only.