Peptide Referee

TB-500: research, legal status and who sells it

TB-500 is sold as a fragment of thymosin beta-4. FDA has identified no human exposure data for it, and WADA bans it.

By Editorial team. Updated Oct 14, 2026. Awaiting expert review

This page is information, not medical advice. TB-500 is not approved as a medicine in the markets below unless stated. We don't publish dosing or usage instructions.

Also known as
Thymosin beta-4 fragment (LKKTETQ), Ac-LKKTETQ
Category
Synthetic fragment of thymosin beta-4
Evidence level
Preclinical (lab and animal studies)
Price range
$1.80/mg to $18.63/mg, median $6.17/mg across 80 vendors (compare)
Our lab tests
None yet (how testing will work)
WhereStatus
United StatesNot FDA-approved; FDA staff recommended against adding TB-500 to the 503A compounding list, and although FDA's advisory committee voted 8–6 to recommend it in July 2026, FDA has not added it [1][2][3].
United KingdomNo UK-licensed medicine containing TB-500 appears in the MHRA products database [4].
European UnionNo medicine containing TB-500 is authorized in the EU, according to EMA's central and Article 57 product data [5][6].
CanadaNo product containing TB-500 appears in Health Canada's Drug Product Database [7].
AustraliaTB-500 and thymosin beta-4 are both Schedule 4 (prescription-only) in Australia's Poisons Standard, with possession without authority prohibited under Appendix D [8].
Sport (WADA)Thymosin beta-4 and its derivatives, including TB-500, are prohibited at all times under S2 [9].
 Summaries of official sources, checked Oct 14, 2026. Rules change; follow the source links. Not legal advice.

What it is

TB-500 is understood to be a seven-amino-acid synthetic fragment of thymosin beta-4 (Tβ4) [2], a naturally occurring 43-amino-acid peptide [10]. Anti-doping chemists identified the acetylated 17–23 fragment of Tβ4, Ac-LKKTETQ, in a product sold as TB-500 [11].

Research status

Most of the research concerns full-length Tβ4, not TB-500; even the three studies cited in TB-500’s compounding nomination were of Tβ4 [2]. Tβ4 sped up healing in animal models of skin wounds and was tested in small phase 2 trials in pressure ulcers, venous ulcers and epidermolysis bullosa wounds [12][10]. For the TB-500 fragment itself, FDA has not identified any human exposure data [13]. A 2026 primer for sports-medicine physicians found that Tβ4 and TB-500 promoted blood-vessel growth and tissue repair in preclinical models, but that human orthopedic data are lacking [14].

Regulatory status

TB-500 is not FDA-approved [1]. FDA staff reviewed it for wound healing and recommended against adding it to the 503A compounding list [2]. FDA’s advisory committee voted 8–6 in favor in July 2026, but the vote is not binding and FDA has not added it [15][3]. In Australia, TB-500 and thymosin beta-4 are Schedule 4 prescription-only poisons, and possession without authority is prohibited [8]. WADA prohibits thymosin beta-4 and its derivatives at all times, naming TB-500 [9].

Quality and testing considerations

FDA has encountered multiple salts and derivatives sold under the TB-500 name [2], and its earlier safety review flagged possible aggregation and peptide-related impurities [13]. Because full-length thymosin beta-4 and the TB-500 fragment are different molecules [11][2], a certificate of analysis should state the exact sequence and molecular mass tested. Thymosin beta-4 was also among the black-market products analyzed by the Cologne anti-doping laboratory in Germany between 2010 and 2013 [16].

Where it’s sold

TB-500 is sold online as a “research use only” product, alone and in blends; the tables below track current listings.

TB-500 compared

TB-500 prices: cheapest listings

The five lowest $/mg listings out of 128. See all TB-500 prices

Vendor Transparency Product Size Price $/mg vs median Stock Vendor's page
Srylab 25/100 TB-500(TB4) 10 mg × 10 $180 $1.80/mg −71% — View
Bulk Peptide Wholesale 45/100* TB-500 10MG (10 vials) 10 mg × 10 $200 $2.00/mg −68% In stock View
Chimera Peptides 27/100 TB500 (Thymosin Beta-4) 10 mg × 10 $204 $2.04/mg −67% In stock View
Srylab 25/100 TB-500(TB4) 5 mg × 10 $105 $2.10/mg −66% — View
Bulk Peptide Supply 57/100* TB-500 10 mg 10 mg $25 $2.50/mg −60% In stock View

Prices come from each vendor's public product feed and were last fetched Oct 15, 2026. They exclude shipping and discounts. $/mg uses the labeled amount, not measured content. A transparency score marked * is based on fewer than six checks; checks we couldn't complete score 0. How we compare prices.

Sources

  1. Drugs@FDA: FDA-Approved Drugs (database searched by active ingredient). U.S. Food and Drug Administration. Accessed Oct 14, 2026
  2. FDA Briefing Document: TB-500-Related Bulk Drug Substances, Pharmacy Compounding Advisory Committee, July 23-24, 2026. U.S. Food and Drug Administration. Accessed Oct 14, 2026
  3. FDA Panel Backs 6 Peptides for Compounding (31 July 2026). AJMC (The American Journal of Managed Care). Accessed Oct 14, 2026
  4. MHRA Products: licensed-medicine search for "thymosin". Medicines and Healthcare products Regulatory Agency (UK). Accessed Oct 14, 2026
  5. EMA medicines data: centrally authorised human medicines (export of 14 October 2026). European Medicines Agency. Accessed Oct 14, 2026
  6. EMA Article 57 product data: medicines authorised in the EU/EEA (data as of 9 October 2026). European Medicines Agency. Accessed Oct 14, 2026
  7. Drug Product Database online query (searched by active ingredient). Health Canada. Accessed Oct 14, 2026
  8. Therapeutic Goods (Poisons Standard—October 2026) Instrument 2026 (F2026L01327, registered 30 September 2026). Federal Register of Legislation, Australian Government. Accessed Oct 14, 2026
  9. World Anti-Doping Code International Standard: Prohibited List 2026 (in force 1 January 2026). World Anti-Doping Agency. Accessed Oct 14, 2026
  10. The effect of thymosin treatment of venous ulcers. Annals of the New York Academy of Sciences (2010). Accessed Oct 14, 2026
  11. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500. Drug Testing and Analysis (2012). Accessed Oct 14, 2026
  12. Thymosin beta 4 Promotes Dermal Healing. Vitamins and Hormones (2016). Accessed Oct 14, 2026
  13. Certain Bulk Drug Substances for Use in Compounding that May Present Significant Safety Risks (content current as of 22 April 2026). U.S. Food and Drug Administration. Accessed Oct 14, 2026
  14. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. American Journal of Sports Medicine (2026). Accessed Oct 14, 2026
  15. July 23-24, 2026: Meeting of the Pharmacy Compounding Advisory Committee. U.S. Food and Drug Administration. Accessed Oct 14, 2026
  16. Identification of black market products and potential doping agents in Germany 2010-2013. European Journal of Clinical Pharmacology (2014). Accessed Oct 14, 2026