TB-500: Thymosin Beta-4 Fragment Research Overview

TB-500 (sometimes written TB500) is a synthetic peptide derived from a specific region of Thymosin Beta-4 (TB4), a 43-amino acid protein that was originally isolated from thymic tissue. Thymosin Beta-4 is one of the most abundant actin-sequestering proteins in mammalian cells and has been studied for decades in cytoskeletal research.^[1]

TB-500 is not the full Thymosin Beta-4 protein but a fragment representing the central actin-binding domain. Research uses the fragment to isolate and study specific signaling activities associated with the actin-binding region, independent of other domains of the full protein.

TB-500 is studied as a research reference compound in controlled preclinical settings. It has not been approved by the FDA for any human therapeutic, diagnostic, or medical purpose.

TB-500 represents the active core fragment of Thymosin Beta-4. Key structural features include:

• Parent protein: Thymosin Beta-4 (43 amino acids)

• Fragment identity: synthetic peptide corresponding to the actin-binding central region

• Form: lyophilized solid

• Disulfide bonds: none (no cysteine residues)

The TB-500 fragment retains the LKKTET actin-binding motif found in Thymosin Beta-4. This conserved sequence is responsible for the protein family's actin-monomer sequestering activity, and its inclusion in the synthetic fragment preserves the actin-binding behavior studied in research models.^[2]

Synthetic TB-500 is produced by solid-phase peptide synthesis to match the natural sequence. Research-grade material is supplied as a lyophilized powder under inert atmosphere.

TB-500 has been studied across several proposed signaling activities, all in preclinical or in vitro systems.

The primary characterized activity of TB-500 (and of its parent Thymosin Beta-4) is binding to G-actin monomers, which influences the equilibrium between monomeric and polymeric actin in cells. This activity has been studied in cell-based assays measuring actin polymerization rates and cytoskeletal organization.^[2][3]

Because actin dynamics underlie cell motility, TB-500 has been examined in cell migration assays. Standard endpoints include wound-closure rates in monolayer scratch assays, transwell migration measurements, and chemotaxis quantification.^[4]

Preclinical studies have examined TB-500 in endothelial cell systems and animal models of vascular formation. Endpoints include tube formation in vitro and capillary density measurements in animal tissue.^[5]

Published TB-500 research has focused on several distinct preclinical domains.

Animal models of tendon and ligament injury have examined TB-500 effects on collagen organization, fibroblast activity, and tissue tensile strength recovery. These studies are conducted entirely in preclinical animal systems and do not extrapolate to human clinical outcomes.^[6]

Cardiac tissue preclinical models have examined TB-500 effects on myocardial repair markers and ischemia-reperfusion damage parameters in rodent systems.^[7]

TB-500 is frequently studied alongside BPC-157 in preclinical literature. The combination is referred to in informal research circles as a 'tissue-repair pair,' reflecting their independent activities at cytoskeletal and growth-signaling pathways respectively.^[8]

TB-500 is supplied as a lyophilized powder. Storage and handling follow standard practices for synthetic peptides.

Lyophilized TB-500 is stored at minus 20 degrees Celsius or colder for long-term preservation. Refrigerated storage (4 degrees Celsius) is acceptable short-term. Reconstituted solution is less stable and is used within 4 to 6 weeks when refrigerated.

Bacteriostatic water (0.9 percent benzyl alcohol) is the most common reconstitution solvent. Sterile water is also used. Reconstitution is performed gently by directing solvent down the vial wall.

Quality verification includes HPLC for purity (greater than or equal to 99 percent), mass spectrometry for identity confirmation, and endotoxin screening. Every batch of Instant Peptides TB-500 ships with a full Certificate of Analysis available via our Lab Tests page.

Instant Peptides supplies TB-500 as a synthetic lyophilized reference compound in 5mg and 10mg vials. Material is supplied to qualified research professionals and scientific institutions. Not for human or animal consumption, diagnostic, or therapeutic use.

View the product page for current pricing and the Certificate of Analysis for the active batch.