28 August 2026
TB-500 Research: The Only Human Trials Are Eye Drops
TB-500 is sold for injury recovery, but thymosin beta-4's only late-stage human trials are eye drops. What the 2026 evidence and Australian rules say.
Peptides · Healing & Recovery
TB-500
Thymosin beta-4 (fragment) · TB4
Unapproved · WADA-prohibited
A synthetic version of thymosin beta-4, a naturally occurring protein involved in cell migration and wound repair. Popular in recovery circles and central to Australia's most famous sports doping saga, its human evidence is limited to small trials in unrelated indications.
At a glance
- Promotes cell migration and vessel growth in animal injury models
- Small human trials only — in eyes and heart, not sports injuries
- Centre of the Essendon saga — 34 players banned by CAS in 2016
- Prohibited at all times under the WADA code
How it works
Thymosin beta-4 regulates actin, a structural protein cells use to move and rebuild. In animal studies it promotes cell migration to injury sites, new blood vessel growth and reduced inflammation — mechanisms relevant to wound, corneal and cardiac repair models.
What the research shows
Animal data in wound healing, corneal injury and cardiac models is genuinely interesting, and small human trials have explored eye drops and cardiac repair. There are no human trials supporting the injury-recovery use it is popularly taken for.
Regulatory status
Australia
Not an approved medicine in Australia and not listed on the ARTG — and controlled earlier than most peptides: thymosin beta-4 entries with Appendix D possession controls took effect in June 2016. It was also at the centre of the Essendon supplements saga, with the CAS banning 34 players for the 2016 AFL season over it.
Worldwide
Not approved by any major regulator. WADA prohibits thymosin beta-4 and its fragments in sport at all times.
Latest TB-500 articles
27 August 2026
TB-500 (Thymosin Beta-4): What the Evidence Actually Shows
TB-500 is sold as a recovery peptide, but the thymosin beta-4 evidence is mostly animal research. What the science, WADA and the TGA actually say.
This is general information, not medical advice. retatrutide.net.au is an independent publication. Unless stated otherwise above, this compound is not an approved medicine in Australia, and this page does not endorse or facilitate its use. Speak to a registered health practitioner about any treatment decision.
Stay informed
Be first to know.
When it reaches Australia.
Retatrutide is not yet available to the public. But when it is, you will want to be first to know. Sign up to receive:
- The latest clinical trial results and news from Eli Lilly
- Updates on TGA regulatory progress in Australia
- How and where to access Retatrutide when it becomes available
- Occasional information from retatrutide.net.au and our affiliated partners
TGA review expected 2027 — subscribers hear the moment the status changes.
Get the free guide + updates
Enter your details once on our free access guide page — instant download, plus we'll email you the moment there's real news.