# Thymosin alpha-1

thymalfasin · Zadaxin · Tα1

https://graded.pl/en/substances/thymosin-alpha-1 · Checked: Not yet

Preliminary version. The editors have not finished checking this card, and grades may change.

A peptide from the thymus gland, studied mainly in chronic hepatitis B. It is a medicine in Italy (Zadaxin) and reported as one in other countries. Not in the US register.

> This site is for information and education only. It does not promote or encourage the use or purchase of the substances described and is not medical advice. Many are not authorised as medicines and their safety has not been established. We sell nothing and have no ties to sellers. For health decisions, consult a doctor.

## Short answers

### Does Thymosin alpha-1 work?

A peptide from the thymus gland, studied mainly in chronic hepatitis B. It is a medicine in Italy (Zadaxin) and reported as one in other countries. Not in the US register. We have not graded the studies yet. The number of papers in the databases is shown on the page.

### Is Thymosin alpha-1 legal?

PL: No approval. The European medicines database (EMA) lists no such medicine in Poland (9 October 2026). The Polish register was down, so we could not check it directly. EU: Approved medicine. No EU-wide approval. Zadaxin (thymalfasin) is approved in Italy (European medicines database, EMA, 9 October 2026). US: No approval. The FDA drug register has no such medicine.

### Is Thymosin alpha-1 banned in sport?

Not on the list, WADA 2026. It is not on the WADA list. The ban does not cover substances approved by an authority, and it is approved in Italy.

### Is Thymosin alpha-1 safe?

Little data. Given to thousands of patients with infections, according to a 2015 review. We found no similar data in healthy people.

## Is it legal

- PL: No approval. The European medicines database (EMA) lists no such medicine in Poland (9 October 2026). The Polish register was down, so we could not check it directly. https://www.ema.europa.eu/en/documents/other/article-57-product-data_en.xlsx (Checked: Not yet)
- EU: Approved medicine. No EU-wide approval. Zadaxin (thymalfasin) is approved in Italy (European medicines database, EMA, 9 October 2026). https://www.ema.europa.eu/en/documents/other/article-57-product-data_en.xlsx (Checked: Not yet)
- US: No approval. The FDA drug register has no such medicine. https://www.accessdata.fda.gov/scripts/cder/daf/ (Checked: Not yet)

## Doping

Not on the list, WADA 2026. https://zoek.officielebekendmakingen.nl/trb-2026-25.html

## How much research exists

- Scientific papers: 890
- Studies with random groups: 64
- Registered studies in people: 66
- These are search results. A count shows how much exists, not how good the studies are. 1 Nov 2026.

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Open data: CC BY 4.0, https://creativecommons.org/licenses/by/4.0/