TB-500 and Thymosin Beta-4: What Researchers Should Know Before Ordering

TB-500 is one of the most searched research peptides and also one of the most loosely described. The name refers to a synthetic peptide based on the sequence of thymosin beta-4, a protein found in most cell types. This guide explains how the two relate, what the preclinical literature covers and what to check before ordering.

Key Facts

• Type: Synthetic peptide based on the sequence of thymosin beta-4 (Tβ4)
• Sequence: Tβ4 has 43 amino acids; the fragment most often sold as TB-500 is Ac-LKKTETQ (residues 17–23)
• Molecular formula: C212H350N56O78S (Tβ4); C38H68N10O14 (Ac-LKKTETQ)
• Molecular mass: about 4,963.4 Da (Tβ4); about 889.0 Da (Ac-LKKTETQ)
• CAS number: 77591-33-4 (Tβ4); 885340-08-9 (Ac-LKKTETQ)
• Supplied as: lyophilized powder in a sealed vial

Thymosin Beta-4 and TB-500

Thymosin beta-4 is a protein of 43 amino acids with a molecular weight of about 4.9 kDa. Its best-described role in the cell is binding actin monomers, which makes it a regulator of the cytoskeleton. TB-500 is a synthetic fragment based on that sequence. Because the name is used for more than one sequence on the market, the Certificate of Analysis is what tells you exactly which one a vial contains.

What the Preclinical Literature Covers

Published work is in cell cultures and animal models. The main topics are:

• Actin binding and cytoskeleton organisation
• Cell migration in culture
• Angiogenesis models
• Tissue models in rodents

These are laboratory findings. CellMind supplies TB-500 strictly for research purposes, not for human consumption.

How Purity and Identity Are Verified

For TB-500, identity matters as much as purity. Mass spectrometry confirms the molecular weight and therefore the sequence; HPLC shows how much of the material is that sequence. Both results belong on a batch-specific Certificate of Analysis. For how to read one, see What Is a CoA and Why Is It the Only Real Proof of Peptide Purity.

Checklist Before You Buy TB-500

• A CoA for the specific batch
• The sequence or molecular weight stated on the report
• HPLC purity stated as a number, above 99%
• The amount per vial stated clearly (10 mg)
• A batch number on the vial that matches the report

Common Questions About TB-500

Is TB-500 the same as thymosin beta-4?

Not necessarily. Thymosin beta-4 is the full protein of 43 amino acids (about 4,963.4 Da). The name TB-500 is also used for a short synthetic fragment, Ac-LKKTETQ (about 889.0 Da).

How can I tell which sequence a vial contains?

By the molecular mass on the report: about 4,963.4 Da points to full-length thymosin beta-4, about 889.0 Da to the fragment. The CoA should state the sequence or the mass.

Storage and Handling

Keep lyophilized vials in a cool, dark place. Once reconstituted, the solution should be refrigerated and used within the planned research window. Avoid repeated temperature changes: they are the most common cause of degradation that nobody notices until results stop matching.

CellMind TB-500 10mg

• 10 mg lyophilized powder per vial, sealed under inert conditions
• HPLC-tested above 99% purity by Janoshik Analytical
• Batch-specific CoA with every order
• Frequently studied alongside BPC-157 in tissue research protocols

Product page for US orders: TB-500 10mg. Reports for current batches: Lab Reports and CoA.

Sources

• Low T.L.K., Hu S.-K., Goldstein A.L. PNAS. 1981;78(2):1162–1166.
• Esposito S. et al. Drug Testing and Analysis. 2012;4(9):733–738.