FDA
No application listedNo application naming thymosin beta 4 or timbetasin or thymosin beta-4 as an active ingredient is listed in Drugs@FDA. Checked 2026-10-05; the control lookup (semaglutide) returned 6 applications.
Drugs@FDA via openFDATB-500: chemistry, literature and regulatory status
Research-use information. This page summarises published literature and regulator records. It is not guidance for use, not medical advice, and not a statement that any material is suitable for use in people or animals.
What is TB-500?
TB-500 is the name used for synthetic thymosin beta 4, a 43-residue peptide that binds G-actin. The catalog lists the full-length sequence. The primary literature indexes the parent peptide as thymosin beta 4, so the studies on this page concern thymosin beta 4. It is supplied here as a research material for laboratory use only.
What are the chemical facts for TB-500?
- Name
- TB-500
- Also written
- Thymosin β4 (1-43); Tβ4
- Sequence
- Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES
- Length
- 43 residues
- Molecular formula
C212H350N56O78S(matches the formula computed from the sequence)- Average molecular weight
- 4963 g/mol
- CAS number
77591-33-4(confirmed in PubChem)- PubChem
- CID 16132341
Chemistry checked against PubChem on 2026-10-05. Where the formula can be computed from the listed sequence, it was, and the two routes agree.
How does the literature describe the mechanism of TB-500?
- Thymosin beta 4 is described as the main G-actin sequestering peptide in mammalian tissue and as a mediator of cell migration, proliferation and differentiation.[5],[4]
- The actin-binding region of thymosin beta 4 was mapped and tested for angiogenic activity in endothelial-cell and tissue assays.[5]
- In a rat full-thickness wound model re-epithelialisation and wound contraction were measured.[6]
- Reviews describe thymosin beta 4 expression across human organs during development, and its role in kidney glomerular cells.[2],[3]
Receptor and pathway background: Thymosin peptides.
What has published research on TB-500 looked at?
6 studies are cited for TB-500. Each is labelled by design below, and each entry says what the paper measured.
- 2 animal study
- 2 review
- 1 human tissue study (review)
- 1 in vitro and animal study
PubMed returns 1195 records for the search terms published on the method page (138 of them with a review publication type, 11 with a clinical-trial publication type), checked 5 October 2026. ClinicalTrials.gov lists 18 registered studies whose intervention matches the name (18 interventional), checked 5 October 2026.
- A 2026 rat study compared BPC-157, synthetic thymosin beta 4 (written TB-500 in that paper) and their combination in an Achilles tendon model.[1]
Studies are listed by what they measured. Papers whose titles state an amount or schedule, or describe a clinical outcome of an approved medicine, are not listed. This is a wording rule, not a quality filter; see the method page.
What is the regulatory status of TB-500?
EMA
No centrally authorised medicine listedNo centrally authorised procedure in the EMA medicines database (checked 5 October 2026) names thymosin beta or timbetasin as an active substance. National authorisations are not in this dataset.
EMA medicines dataMHRA
No product document foundNo SmPC, PIL or PAR document in MHRA Products matches the exact name "thymosin beta 4" or "timbetasin". Checked 2026-10-05; the control lookup (semaglutide) returned 271 documents.
MHRA ProductsWADA
Named, S2.3The WADA 2026 Prohibited List, in force 1 January 2026 names TB-500 under S2.3 (growth factors and growth factor modulators). A WADA entry is a sporting rule, not a statement about legality outside sport.
WADA Prohibited List 2026The WADA 2026 list names thymosin beta 4 and its derivatives, with TB-500 as the example.
A regulator record is information about a database entry. It is not advice and not a statement that any use is lawful or unlawful in any country. How regulators approach research peptides.
Data dates: regulatory records 2026-10-05; WADA list 2026-10-05.
Which studies are cited for TB-500?
[1] Biçer O, Adanir O, Güleryüz Y, Balci EC, Dinçel YM, Yenigün MY, et al.. Effects of BPC-157 and TB-500 on Achilles tendon healing in rats: A histopathological and biomechanical study. Jt Dis Relat Surg. 2026;37:822-837.
Compared BPC-157, synthetic thymosin beta 4 (TB-500) and their combination in a rat Achilles tendon model with biomechanical and histological analyses.
[2] Faa G, Messana I, Coni P, Piras M, Pichiri G, Piludu M, et al.. Thymosin β4 and β10 Expression in Human Organs during Development: A Review. Cells. 2024;13.
Review of the authors' proteomic and tissue data on thymosin beta 4 and beta 10 expression across human organs during development.
[3] Mason WJ, Vasilopoulou E. The Pathophysiological Role of Thymosin β4 in the Kidney Glomerulus. Int J Mol Sci. 2023;24.
Review of thymosin beta 4 in kidney glomerular cells and glomerular disease models.
[4] Goldstein AL, Hannappel E, Sosne G, Kleinman HK. Thymosin β4: a multi-functional regenerative peptide. Basic properties and clinical applications. Expert Opin Biol Ther. 2012;12:37-51.
Review of thymosin beta 4 properties: actin binding, cell migration and reported tissue-repair roles.
[5] Philp D, Huff T, Gho YS, Hannappel E, Kleinman HK. The actin binding site on thymosin beta4 promotes angiogenesis. FASEB J. 2003;17:2103-5.
Mapped the actin-binding region of thymosin beta 4 and tested its angiogenic activity in endothelial-cell and tissue assays.
[6] Malinda KM, Sidhu GS, Mani H, Banaudha K, Maheshwari RK, Goldstein AL, et al.. Thymosin beta4 accelerates wound healing. J Invest Dermatol. 1999;113:364-8.
Measured wound re-epithelialisation and contraction in a rat full-thickness wound model.
Data dates: citations read from PubMed 2026-10-05.
Where else in the research library is TB-500 covered?
Who wrote this page and how is it checked?
Peptency editorial team, last reviewed 5 October 2026. Citations are read back from PubMed, chemistry is checked against PubChem, and regulator records are read from each regulator's own database on the dates shown. The method page lists every source, search term and rule. Corrections are welcome through the contact details on the About page.