Scientifically reviewed by Dr Stephan Hansberg
Is TB-500 legal? US, UK and Australia status (2026)
The legal status of TB-500, the synthetic thymosin beta-4 fragment, in the US, UK and Australia as of October 2026, plus its WADA S2 status and what the July 2026 FDA advisory vote did and did not change.
Key takeaways
- •TB-500 is a synthetic peptide based on the actin-binding region of thymosin beta-4; the FDA lists it as thymosin beta-4 fragment (LKKTETQ).
- •US: Category 2 from September 2023, off Category 2 in April 2026, recommended for the 503A bulks list 8-6 with one abstention in July 2026; rulemaking pending.
- •UK: not a controlled drug and not a licensed medicine; medicines law applies when it is presented or used as a medicine.
- •Australia: thymosin beta-4 and TB-500 were brought into Schedule 4 with an Appendix D possession offence in 2016, and TB-500 is named in the TGA's 2026 enforcement priority.
- •Sport: named in S2.3 of the WADA List (thymosin beta-4 and its derivatives), prohibited at all times as a non-Specified Substance.
The short answer
TB-500 is not an approved medicine in the US, UK or Australia. In the US and UK it is not a controlled drug, so the legal issue is how it is sold and presented, while in Australia thymosin beta-4 and TB-500 are Schedule 4 substances that are illegal to possess without authority.
TB-500 is the name used for a synthetic peptide modelled on the actin-binding region of thymosin beta-4, a naturally occurring 43-amino-acid protein. Thymosin beta-4 has been studied in cell and animal models of tissue repair and cell migration. The FDA's compounding lists refer to it as thymosin beta-4, fragment (LKKTETQ).
TB-500 status at a glance (October 2026)
| Jurisdiction | Regulator | Status | Most recent change |
|---|---|---|---|
| United States | FDA | Not FDA-approved; not a controlled substance; not on the 503A bulks list | PCAC recommended bulks list inclusion, 23 Jul 2026 (8-6, 1 abstention); rulemaking pending |
| United Kingdom | MHRA | Not a licensed medicine; not a controlled drug | No TB-500-specific change; MHRA enforcing against medicinal claims in 2026 |
| Australia | TGA | Schedule 4 with Appendix D possession offence (thymosin beta-4 and TB-500) | Named in TGA compliance priority, Jun 2026 |
| Sport (WADA) | WADA | S2.3, thymosin beta-4 and its derivatives e.g. TB-500; non-Specified; prohibited at all times | Unchanged on 2026 List |
United States
The FDA placed thymosin beta-4 fragment (LKKTETQ) in 503A Category 2 on 29 September 2023, noting a possible risk of immunogenicity for some routes of administration due to aggregation and peptide-related impurities. On 22 April 2026 it was moved off Category 2 after the nominators withdrew, and it now appears on the FDA's list of nominated but withdrawn substances.
On 23 July 2026 the Pharmacy Compounding Advisory Committee voted 8-6 with one abstention to recommend adding TB-500 free base and acetate to the 503A bulks list. As with BPC-157, this was against the FDA staff recommendation and is not binding. Until the FDA completes rulemaking, TB-500 is not on the bulks list. It is not a controlled substance, and selling it with human-use claims would make it an unapproved new drug.
United Kingdom
TB-500 is not controlled under the Misuse of Drugs Act 1971 and has no UK marketing authorisation. The Human Medicines Regulations 2012 apply when a product is presented as a medicine or used to modify physiological function in people, and the MHRA's 2026 statements on peptide clinics make clear that medicinal claims bring a peptide inside that regime. Research use only supply, consistently presented as such, sits outside it.
Australia
Thymosin beta-4, TB-500 and fibroblast growth factors were considered by the TGA's medicines scheduling committee in 2015 after an application from the national sport integrity unit, and the delegate confirmed their inclusion in Schedule 4 and Appendix D, item 5, the list of poisons for which possession without authority is illegal. The change was implemented in the Poisons Standard that commenced on 1 June 2016.
TB-500 was named in the TGA's June 2026 enforcement priority and its joint statement with the Chief Medical Officer, and a BPC-157 and TB-500 combination was among products seized in New South Wales in August 2026. The TGA has said it is unlawful to import, advertise, manufacture or supply unapproved peptide products in Australia.
Sport: WADA and NCAA
The 2026 WADA List names thymosin beta-4 and its derivatives, for example TB-500, under S2.3, growth factors and growth factor modulators. S2 substances are prohibited at all times and are non-Specified, which means higher default sanctions than S0. USADA's advisory on the 2027 List also lists TB-500 among peptides athletes must avoid.
The NCAA's 2026-27 banned substances list names TB-500 among its peptide hormone and growth factor examples.
Where Celyfe fits
Celyfe supplies TB-500 only in combination pens: WOLVERINE (BPC-157 15 mg and TB-500 15 mg), GLOW (adds GHK-Cu 75 mg) and KLOW (adds KPV 15 mg), each a pre-filled 3 ml cartridge. WOLVERINE batch C26071 tested at 99% purity by HPLC at the independent laboratory Analiza Bialek, Wroclaw, Poland, report dated 2 October 2026. GLOW and KLOW certificates are listed in the COA library when published.
Sources
Checked 8 October 2026:
- FDA: Certain bulk drug substances for use in compounding that may present significant safety risks (thymosin beta-4 fragment entry dated 29 Sep 2023; current page as of 22 Apr 2026), fda.gov
- FDA: July 23-24, 2026 meeting of the Pharmacy Compounding Advisory Committee, fda.gov
- The FDA Law Blog: PCAC approves four bulk drug substances for the 503A list, 24 Jul 2026
- TGA: Scheduling decisions, performance and image enhancing drugs (thymosin beta-4, TB-500), ACMS November 2015, tga.gov.au
- Explanatory statement, Poisons Standard June 2016 (F2016L00849), commenced 1 Jun 2016, legislation.gov.au
- TGA media releases on unapproved peptides, 10 Jun, 19 Jun and Aug 2026, tga.gov.au
- Sport Integrity Australia: Thymosin beta-4 substance profile, sportintegrity.gov.au
- WADA: Prohibited List 2026 (S2.3), wada-ama.org
- USADA: What's new on the 2027 WADA Prohibited List, usada.org
- NCAA: 2026-27 banned substances list, ncaa.org
Research use only
Celyfe supplies research peptides for laboratory and research use only. Nothing on this page is guidance on use in humans or animals. This is general information, not legal advice. Rules in all three countries changed several times in 2026, so check the regulator's current publications or speak to a qualified adviser before relying on anything here.
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