TB-500

TB-500 is a synthetic fragment of Thymosin β-4, a 43-amino-acid actin-sequestering peptide naturally abundant in platelets, fibroblasts, and wound exudate. Thymosin β-4 is one of the most abundant intracellular proteins in mammalian cells, where it serves as the principal G-actin binding protein.

TB-500 binds G-actin monomers via the conserved LKKTET motif, sequestering them from polymerization into F-actin filaments. This regulation of the actin cytoskeleton supports cell motility, with downstream effects on endothelial cell migration in scratch-wound assays. PI3K/Akt signaling has been reported as a downstream pathway in cell-culture work. Tissue distribution and stability differ between the natural Thymosin β-4 protein and the synthetic TB-500 fragment, which is sometimes acetylated at the N-terminus to extend in vitro stability.

Used in vascular biology and cardiac repair research, dermal regeneration models, and corneal wound healing assays. Frequently paired with BPC-157 in pre-clinical tissue repair studies in the published literature.

Every batch ships with a third-party Certificate of Analysis documenting identity, lot-specific HPLC purity, mass spectrometry confirmation, and storage conditions. The COA is downloadable from the buyer's account dashboard and QR-linked on the vial label. Purity claims are per lot, not per product — see the FAQ for the framing.

Sold under one of two B2B buyer categories: research institutions for in vitro work under the RUO designation, or licensed 503A compounding pharmacies as an API for patient-specific compounded preparations under USP <797> or <795>. Accounts are manually reviewed; pending accounts cannot place orders or view pricing.

The full regulatory framing, including what we are not (we are not a 503B outsourcing facility and do not compound finished drugs), is in the disclaimer.