TB-500: what is it and what does research say?

Thymosin beta-4 (Tβ4) is a protein of 43 amino acids found in almost all human and animal cells. It is one of the main proteins that bind free actin molecules (G-actin) in the cell.

TB-500 is the trade name for synthetic research material based on this protein, in particular on its actin-binding region. It is supplied as a freeze-dried powder in a vial.

The name TB-500 is not used for one fixed substance in the market, so it pays to read the certificate.

• Full thymosin beta-4: the complete 43-amino-acid peptide, with a molecular mass of about 4.9 kDa.
• The short fragment: a seven-amino-acid piece of the actin-binding region (Ac-LKKTETQ, amino acids 17–23), with a much lower mass.
• Which substance is in a vial shows in the mass measured by mass spectrometry (MS). A good certificate of analysis states it.

Research into thymosin beta-4 and TB-500 takes place in cell and animal models. The literature focuses mainly on how the peptide binds actin and what that means for the cell.

• Actin binding: how Tβ4 holds free actin molecules and so affects how the cytoskeleton is built.
• Cell migration: how cells move and relocate in culture models.
• Angiogenesis: the formation of new blood vessels in experimental models.

TB-500 has no marketing authorisation anywhere. It is intended solely as research material for laboratory use, not for human or animal consumption. That is why a pharmacy does not sell it; you buy it from a supplier of research peptides.

At BrabantLabs every certificate is online under lab results, searchable by product and lot number. The current price per strength is on the TB-500 product page.

• A certificate of analysis per lot, with purity measured by HPLC.
• A mass measurement (MS) that shows which substance you get: full Tβ4 or the short fragment.
• A lot number on the vial that matches the lot on the certificate.
• The net amount per vial in mg, so you can calculate the concentration of your solution.

• As powder: briefly in the fridge (2–8 °C), longer in the freezer (−20 °C or colder). Let the vial reach room temperature before opening it.
• Dissolving: in bac water, following the steps in Dissolving peptides. Work out the concentration with the peptide calculator.
• Dissolved: in the fridge, do not freeze, and use within about 28 days.

The price depends mainly on the amount per vial (mg), the measured purity and whether an independent lab tested every lot. A low price without a certificate says little: without an MS measurement you do not even know which substance is in the vial.

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

Not always. Some suppliers sell the full 43-amino-acid peptide as TB-500, others the seven-amino-acid fragment. The mass measurement on the certificate shows which of the two you have.

How do you store TB-500?

As powder briefly in the fridge and longer in the freezer (−20 °C or colder). Dissolved, in the fridge, not frozen, and used within about 28 days.

Why does a certificate of analysis matter?

The certificate shows the purity (HPLC) and identity (MS) of exactly the lot you receive. Without it you cannot check what is in the vial.

Can I order TB-500 and BPC-157 together?

Yes. The shop also lists them as a fixed bundle, with a 10% bundle discount on the complete set.

• View TB-500 in the shop