TB-500
Thymosin Beta-4 active fragment
Synthetic active region of Tβ4
A synthetic peptide corresponding to a biologically active fragment of Thymosin Beta-4 (Tβ4), a 43-residue peptide naturally present in many mammalian tissues. Sold for in vitro laboratory research and analytical use only.
The active fragment of a naturally-occurring 43-residue peptide.
TB-500 is a synthetic peptide corresponding to the biologically active region of Thymosin Beta-4 (Tβ4), a 43-amino-acid peptide first isolated from calf thymus tissue. Tβ4 belongs to the β-thymosin family — small proteins broadly distributed across mammalian tissues, found at particularly high concentrations in blood platelets and in tissues undergoing active repair. It is among the most abundant intracellular peptides in many mammalian cell types.
Tβ4's best-characterized biochemical function is the sequestration of monomeric G-actin: it forms a 1:1 complex with G-actin, buffering the pool of available monomer and regulating the rate of filament assembly and disassembly. The central actin-binding motif is the LKKTET hexapeptide — a sequence conserved across the β-thymosin family. TB-500 encompasses this region, making it the pharmacologically active portion of the molecule in cytoskeletal experiments.
The cell-biology literature on Tβ4 and TB-500 is mature. Studies have characterized its role in cell migration — actin dynamics being central to lamellipodia formation — along with effects on proliferation, survival signaling, and extracellular matrix remodeling in a variety of culture systems. A notable line of work involves integrin-linked kinase (ILK) activation, through which Tβ4 has been proposed to promote cell survival and directed migration independently of its direct actin-sequestering function.
The translational literature — animal models of tissue injury — spans cardiac, dermal, and corneal tissue. A particular concentration of published work addresses cardiac repair following ischemia: studies in rodent and porcine models have examined Tβ4's effects on cardiomyocyte survival, neovascularization, and functional recovery post-infarction. The corneal wound healing literature is the most clinically advanced area, encompassing a small number of human ophthalmic trials investigating topically applied Tβ4 for corneal injuries.
Researchers working with TB-500 will encounter two distinct entities in the published literature: full-length Thymosin Beta-4 (the complete 43-residue peptide) and the shorter active fragment sold as TB-500. Secondary sources do not always distinguish between them clearly. Before drawing mechanistic conclusions or comparing across studies, confirm whether a given paper used recombinant full-length Tβ4 or the shorter active-region fragment — pharmacokinetics, receptor interactions, and actin-binding kinetics may differ in ways that are relevant to experimental design.
Identity and storage.
| Compound | TB-500 (Tβ4 active fragment) |
| Form | Lyophilized white powder |
| Purity (HPLC) | ≥98.0% |
| Storage (sealed) | -20°C, dry, dark |
| Storage (reconstituted) | 4°C, ≤30 days |
| Reconstitution solvent | Bacteriostatic water |
Every TB-500 batch we have shipped.
Reverse chronological. Nothing deleted.
| Batch ID | COA date | Purity | Notes | Document |
|---|---|---|---|---|
| B-2603-021 | 2026-03-28 | ≥98.1% | — | [PDF] |
| B-2602-014 | 2026-02-19 | ≥98.0% | — | [PDF] |
See destroyed batches on the transparency log →
Research-use-only disclosure.
Foundational literature.
- Goldstein A.L. et al. (2005). Thymosin beta-4: actin-sequestering protein moonlights to repair injured tissues. Trends in Molecular Medicine, 11(9):421–429.
- Sosne G. et al. (2007). Thymosin beta 4 inhibits TNF-alpha-induced NF-kB activation and thereby prevents corneal stromal fibroblast senescence. Experimental Eye Research, 84(4):663–669.
- Bock-Marquette I. et al. (2004). Thymosin β4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair. Nature, 432(7016):466–472.