TB-500

The name TB-500 is not used consistently across the research-supply market. In analytical literature, TB-500 has been described as the N-terminally acetylated fragment 17–23 of thymosin beta-4 — the heptapeptide Ac-LKKTETQ (Esposito et al. 2012; Ho et al. 2012; model types: analytical). The wider biological literature, however, examines full-length thymosin beta-4 (Tβ4), a 43-amino-acid actin-binding peptide. The molecules are related but not chemically identical — and that difference decides which studies apply to the material in a vial.

Reborn resolves this ambiguity per batch: the released material is full-length thymosin beta-4, and its identity is confirmed by mass spectrometry in the batch certificate of analysis — 4963.4 Da and ~889 Da do not describe the same substance, so the analytical mass on the COA settles the question for every batch.

Sources: Esposito 2012 · PMID 22962027 · Ho 2012 · PMID 23084823

Actin exists as soluble G-actin and can polymerise into filamentous F-actin; the balance between the two contributes to cell shape, movement and measurable remodelling processes. Thymosin beta-4 is biochemically characterised as an actin-sequestering peptide: Safer and colleagues found it indistinguishable from the actin-binding peptide previously called “Fx” and demonstrated binding to actin monomers (1991; model type: in-vitro biochemistry).

Sanders and colleagues subsequently showed that full-length Tβ4 altered actin polymerisation and reduced visible stress fibres in a concentration-dependent manner in epithelial cells and fibroblasts (1992; model type: in vitro). These are defined mechanistic reference points — observed cellular processes under controlled conditions, not evidence of any effect outside those models.

For laboratory work, the productive research question is therefore: which molecular form is present, which actin-related endpoint is being measured, and can the analytical method distinguish the fragment from full-length Tβ4?

Sources: Safer 1991 · PMID 1999398 · Sanders 1992 · PMID 1584803

The findings below describe outcomes in controlled preclinical research. They do not establish an approved use, support self-experimentation or predict an outcome outside the cited studies.

Most frequently cited papers concern full-length thymosin beta-4 in cell or animal models. Results from these models cannot be generalised to humans, and no finding on this page is a statement about effects, benefits or safety outside the cited study. Thymosin beta-4 is not an approved medicine.

Evidence from different molecules must also not be pooled: Ac-SDKP is a distinct Tβ4 fragment with its own literature, and other research peptides sold alongside TB-500 are separate substances with separate evidence bases. Studies of individual components never establish a combined effect for a multi-component product.

This TB-500 research peptide is supplied as 10 mg of lyophilised material per vial. Lyophilised peptides are stored dry, protected from light and refrigerated; temperature cycling and moisture ingress are the practically relevant quality risks (Wang 2000; review of the stability and storage of lyophilised peptide preparations).

Batch documentation: A certificate of analysis connects the batch number, test date, identity method and analytical result. For TB-500 this reconciliation is decisive, because the market name covers different molecular forms — the measured mass in the COA confirms what is actually in the vial. Purity information is always batch-specific; this page makes no blanket purity claim.

Source: Wang 2000, Int. J. Pharmaceutics · PMID 10967427

Reborn lists TB-500 exclusively as a laboratory research material for laboratories and researchers across the EU. Ten PubMed-indexed sources — from foundational actin biochemistry through rodent remodelling models to the analytical identity literature — document the research landscape, and every scientific claim in this section is tied to one of them.

Research use only. For laboratory research only. Not for human or veterinary use. Not intended to diagnose, treat, cure or prevent any disease. Not a medicinal product, food or cosmetic.