TB-500 (Thymosin Beta-4): Research Guide for Canadian Labs

TB-500 is the research-market name for synthetic thymosin beta-4 (Tβ4), a 43-amino-acid peptide that binds monomeric actin — and some suppliers also use the name for shorter fragments of it. Thymosin beta-4 is one of the most abundant intracellular peptides in mammalian cells and is studied in laboratory models of cell migration and tissue repair. It is not an authorized drug in Canada; this page covers it as a laboratory research reagent only.

TB-500 at a glance

Property	Detail
Parent molecule	Thymosin beta-4 (Tβ4)
Length	43 amino acids (full-length), N-terminally acetylated
Molecular weight	≈ 4.96 kDa for full-length thymosin beta-4
Key region	Central actin-binding motif LKKTETQ (residues 17–23)
Related fragments	“TB-500 fragment” products and the N-terminal tetrapeptide Ac-SDKP
Usual supplied form	Lyophilized powder in a sealed vial
Status	Not an authorized drug; sold for laboratory research use only

TB-500, thymosin beta-4 and fragments: what the names mean

“Thymosin beta-4” is the scientific name of the native 43-residue peptide. “TB-500” is a trade name used by research-chemical suppliers, and it is not applied consistently: many supplier listings use it for synthetic full-length thymosin beta-4, while others use it for a short synthetic fragment built around the LKKTETQ actin-binding sequence. Two anti-doping laboratory studies published in 2012 described TB-500 as the N-terminally acetylated 17–23 fragment (Ac-LKKTETQ), not the full-length peptide. The two differ greatly in mass, so mass-spectrometry identity data is the reliable way to know which one is in a vial. That is why TB-500 (Thymosin Beta-4) and TB-500 Fragment are listed as separate products here.

What thymosin beta-4 research covers

Thymosin beta-4 sequesters G-actin and so influences actin polymerization, which is why it appears in research on cell migration and cytoskeletal dynamics. Preclinical studies have examined it in wound-repair, angiogenesis, corneal and cardiac injury models, and the N-terminal fragment Ac-SDKP has its own literature in fibrosis and inflammation models. These are cell-culture and animal findings; they are not evidence of any effect in people.

TB-500 vs BPC-157

TB-500 and BPC-157 are often discussed together in tissue-repair research, but they are unrelated in structure and mechanism: thymosin beta-4 is a 43-residue actin-binding peptide of about 4.96 kDa, while BPC-157 is a 15-residue peptide of about 1.4 kDa. Read the BPC-157 vs TB-500 comparison or the BPC-157 research guide.

How to verify a TB-500 batch

• Identity by mass spectrometry — confirm the observed mass matches full-length thymosin beta-4 (≈ 4.96 kDa) or the specific fragment stated on the label. This is the check that tells full-length material and fragments apart.
• Purity by HPLC — read the chromatogram as well as the percentage; see the HPLC testing guide.
• Batch match — the certificate’s lot number must match the vial. Janoshik reports for TB-500 and TB-500 Fragment are listed on the lab testing page.
• Net peptide content — larger peptides carry more counter-ion and water mass; the COA guide explains how to account for it.

Storage and handling

Store sealed lyophilized vials cold, dry and dark, warm a vial to room temperature before opening, and aliquot reconstituted stock to avoid repeated freeze-thaw cycles. See the peptide storage guide.

Sourcing TB-500 in Canada

Pure Peptides Canada supplies full-length TB-500 (thymosin beta-4), TB-500 Fragment and a BPC-157 + TB-500 blend for laboratory research, shipped tracked from within Canada with batches matched to independent Janoshik reports.

Frequently asked questions

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For laboratory and research use only. Not for human or veterinary use, consumption, or administration. Nothing on this page is medical advice or a claim that any compound diagnoses, treats, cures, or prevents any condition. Purchasers confirm they are qualified to handle research materials and are of legal age in their province.

References

1. Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opinion on Biological Therapy. 2012;12(1):37–51. Review of thymosin beta-4’s basic biology and of the tissue-repair research in which it has been studied.
2. Xing Y, Ye Y, Zuo H, Li Y. Progress on the function and application of thymosin β4. Frontiers in Endocrinology. 2021;12:767785. Open-access review covering thymosin beta-4’s 43-amino-acid structure, its binding of G-actin, the 17–23 active fragment and the Ac-SDKP metabolite.
3. Esposito S, Deventer K, Goeman J, Van der Eycken J, Van Eenoo P. Synthesis and characterization of the N-terminal acetylated 17-23 fragment of thymosin beta 4 identified in TB-500, a product suspected to possess doping potential. Drug Testing and Analysis. 2012;4(9):733–738. Reports that a product sold as TB-500 contained the N-terminally acetylated 17–23 fragment of thymosin beta-4 (LKKTETQ), characterized by high-resolution LC-MS and NMR.
4. Ho ENM, Kwok WH, Lau MY, Wong ASY, Wan TSM, Lam KKH, et al. Doping control analysis of TB-500, a synthetic version of an active region of thymosin β4, in equine urine and plasma by liquid chromatography-mass spectrometry. Journal of Chromatography A. 2012;1265:57–69. Describes an LC-MS method for detecting N-acetylated LKKTETQ, the synthetic thymosin beta-4 fragment the authors identify as TB-500.
5. Wang W, Jia W, Zhang C. The role of Tβ4-POP-Ac-SDKP axis in organ fibrosis. International Journal of Molecular Sciences. 2022;23(21):13282. Review of how prolyl oligopeptidase cleaves thymosin beta-4 to release the tetrapeptide Ac-SDKP, and of research on this pathway in fibrosis models.