One name, several products
Thymosin beta-4 is a 43-amino-acid protein found naturally in the body. "TB-500" is not a scientific name; it is a label used in the market.
PubChem's TB-500 entry is the short fragment LKKTETQ, 7 amino acids at 889.0 g/mol. Some sellers supply an acetylated version of that fragment, and some supply the full-length protein at about 4,963 g/mol, all under the same name.
How to tell them apart
The mass is the giveaway. A mass spectrometry report on the certificate of analysis should show a mass that matches the product named on the label. A 7-amino-acid fragment and the full 43-amino-acid protein differ by more than 4,000 g/mol, so the two cannot be confused on a genuine report.
Regulatory and sporting status
TB-500 is not an approved medicine in the UK, the EU or the US.
The World Anti-Doping Agency prohibits thymosin beta-4 and its derivatives, naming TB-500, under growth factors.
Educational information only. Nothing here is medical advice, dosing guidance or a recommendation to use any substance. Research peptides are not approved medicines and are not for human or animal consumption. Speak to a qualified professional and follow the law where you are.
