# TB-500

thymosin beta-4 · Tβ4 · timbetasin

https://graded.pl/en/substances/tb-500 · Checked: Not yet

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

This name is used for thymosin beta-4 or a short piece of it. A test of products sold online found contents that did not match their description.

> 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 TB-500 work?

This name is used for thymosin beta-4 or a short piece of it. A test of products sold online found contents that did not match their description. Recovery and injury: grade D, not clear. In one study of tendons in rats, TB-500 improved early healing. There is no study of this fragment in people.

### Is TB-500 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: No approval. The European medicines database (EMA), which covers EU and national approvals, lists no such medicine (9 October 2026). US: No approval. No approved medicine. On 30 October 2026 the US health department (HHS) published a draft policy: it does not plan to act against pharmacies and doctors that make it on a prescription for a named patient, from an FDA-registered maker, until the FDA decides by rule. The draft is not binding, and comments close on 13 November 2026.

### Is TB-500 banned in sport?

Banned in sport, WADA 2026.

### Is TB-500 safe?

Not known. Studies of thymosin beta-4 do not test this fragment. A 2026 review says very little is known about the safety of peptides like this one in people.

## What studies show

| | | | |
|---|---|---|---|
| Recovery and injury | D | Not clear | In one study of tendons in rats, TB-500 improved early healing. There is no study of this fragment in people. |

## Studies we have read

- Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. (Joint diseases and related surgery 2026; In animals, n=32) https://pubmed.ncbi.nlm.nih.gov/42542926/

## 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: No approval. The European medicines database (EMA), which covers EU and national approvals, lists no such medicine (9 October 2026). https://www.ema.europa.eu/en/documents/other/article-57-product-data_en.xlsx (Checked: Not yet)
- US: No approval. No approved medicine. On 30 October 2026 the US health department (HHS) published a draft policy: it does not plan to act against pharmacies and doctors that make it on a prescription for a named patient, from an FDA-registered maker, until the FDA decides by rule. The draft is not binding, and comments close on 13 November 2026. https://www.federalregister.gov/documents/2026/10/30/2026-22192/enforcement-discretion-policy-regarding-503a-compounding-using-certain-peptide-bulk-drug-substances (Checked: Not yet)

## Doping

Banned in sport, WADA 2026. https://zoek.officielebekendmakingen.nl/trb-2026-25.html

## How much research exists

- Scientific papers: 632
- Studies with random groups: 3
- Registered studies in people: 19
- 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/