TB-500: Research, Handling and Batch Documentation

Identity and research status

Also referred to as

Thymosin Beta-4, Tβ4, Timbetasin

Sequence

Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln

Single-letter Code

Ac-LKKTETQ

Molecular Weight

889.02 g/mol

Length

7 amino acids, N-terminally acetylated

Corresponds To

Residues 17 to 23 of thymosin beta-4

Parent Protein

Thymosin beta-4, 43 amino acids, PubChem CID 45382195

Parent Protein Formula

C212H350N56O78S

Parent CAS Number

77591-33-4 designates thymosin beta-4, the full-length protein

Active Motif

LKKTET, the actin-binding sequence

Appearance

White lyophilised powder

Mechanism, in brief

TB-500 is the synthetic N-acetylated heptapeptide Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln, corresponding to residues 17 to 23 of thymosin beta-4. It is not thymosin beta-4 itself. Thymosin beta-4 is a 43 residue protein and one of the most abundant intracellular proteins in mammalian cells; TB-500 is the short fragment containing the actin-binding motif that carries much of the extracellular activity.

1. Actin monomer binding. The LKKTET motif binds monomeric G-actin, which in the parent protein maintains a sequestered reserve available for rapid filament assembly during migration and remodelling.
2. Cell migration. By influencing actin dynamics, the peptide is reported to promote migration of endothelial, epithelial and other cell types, which is the proposed basis for its wound repair effects.
3. Angiogenic signalling. Thymosin beta-4 promotes endothelial cell migration and tube formation, contributing to new vessel formation in injury models.
4. Integrin-linked kinase and Akt activation. Cardiac work reports that thymosin beta-4 activates integrin-linked kinase and downstream Akt signalling, associated with improved cardiomyocyte survival after ischaemic injury.
5. Anti-inflammatory and repair signalling. Reported reductions in inflammatory mediators, and in one model promotion of autophagy through HIF-1 alpha stabilisation, describe a repair-permissive rather than purely structural role.

The full research write-up, including the findings behind each claim and the model each came from, is on the TB-500 10mg 10mg page.

Vial sizes available

Every size of TB-500 Volta lists, in stock or not. Each is a separate catalogue page with its own batch number and specification table.

• TB-500 10mg 10mgBatch #: VPTB10100
  In stock
• TB-500 5mg 5mgBatch #: VPTB5100
  Restocking

Purity and batch documentation

Volta's release specification is >99% (HPLC). That is a threshold we set. >99% is the specification every batch is released to. The figure on a certificate is what a laboratory measured for one lot.

• SideChain Analytics reported 99.5% by HPLC-MS/MS on September 24, 2026.

  Covers the TB-500 10mg vial.

  Read the certificateVerify on lab's website (Verify on SideChain Analytics's website, opens in a new tab)

Research on TB-500

Handling and stability

Regulatory context

United States

Not FDA-approved. Removed from Category 2 on April 15, 2026. PCAC review pending July 2026. Previously classified as Category 2 since September 2023. WADA-banned (S2 growth factor).

Canada

Not approved by Health Canada.

United Kingdom

Not MHRA-approved.

• the legal status of research peptides in Canada
• Health Canada's regulatory position

Primary sources

1. Bock-Marquette I, Saxena A, White MD, et al.. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature (2004). PMID 15565145
2. Sosne G, Qiu P, Goldstein AL, Wheater M. Biological activities of thymosin beta4 defined by active sites in short peptide sequences. FASEB Journal (2010). PMID 20179146
3. Sosne G, Dunn SP, Kim C. Thymosin beta 4 significantly improves signs and symptoms of severe dry eye in a phase 2 randomized trial. Cornea (2015). PMID 25826322
4. Sosne G, Ousler GW. Thymosin beta 4 ophthalmic solution for dry eye: a randomized, placebo-controlled, Phase II clinical trial. Clinical Ophthalmology (2015). PMID 26056426
5. Kim JH, Lim IR, Joo HJ, et al.. Thymosin beta4-Enhancing Therapeutic Efficacy of Human Adipose-Derived Stem Cells in Mouse Ischemic Hindlimb Model. International Journal of Molecular Sciences (2020). PMID 32245208
6. Renga G, Oikonomou V, Stincardini C, et al.. Thymosin beta4 promotes autophagy and repair via HIF-1 alpha stabilization in chronic granulomatous disease. Life Science Alliance (2019). PMID 31719116
7. Nguyen J, Verma S, et al.. Engineered Tandem Thymosin Peptide Promotes Corneal Wound Healing. Investigative Ophthalmology and Visual Science (2025). PMID 41235866