# TB-500 in Australia: What It Is and How It Is Tested

TB-500 is a lab-made peptide copying seven amino acids of thymosin beta-4, and Australian Research Peptides supplies it across Australia to laboratories and researchers as a single freeze-dried vial posted from Sydney. The fragment copies only the actin-binding stretch of its 43-residue parent protein. Its identity is confirmed by HPLC and mass spectrometry, and the weight difference lets a laboratory tell the short fragment from the full protein. Supplied for in vitro research purposes only.

- Source: https://www.australianresearchpeptides.au/articles/tb-500-australia
- Reading time: 4 minute read
- Published: 2026-09-24
- Publisher: Australian Research Peptides

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In vitro research only.

This guide describes a research compound and the published laboratory work on it. Nothing here is an amount, a schedule, a route or advice about use in a person or an animal.

## What Is TB-500?

TB-500 is a synthetic peptide made of seven amino acids, written Ac-LKKTETQ, that reproduces one short stretch of a naturally occurring protein called thymosin beta-4. The “Ac” is an acetyl group capping the front end of the chain.

Chemists call a seven-residue chain a heptapeptide. Buyers type the name several ways — TB500, TB 500, TB-500 — and all of them mean the same short fragment. PubChem indexes it as a single compound record, with a free-acid molecular weight of about 889 g/mol.

## Is TB-500 the Same as Thymosin Beta-4?

TB-500 is not the same as thymosin beta-4. Thymosin beta-4 is a protein of 43 amino acids weighing roughly 5 kDa, and TB-500 copies only seven of them — the stretch at positions 17 to 23 that holds on to actin.

For a buyer that has two practical consequences. First, a paper about the whole protein is not automatically a paper about the fragment, so a claim should be traced to the molecule it was measured on. Second, the size gap is large enough that a laboratory can tell the two apart by weight alone, which is the subject of the testing section below. [BPC-157 vs TB-500](https://www.australianresearchpeptides.au/articles/bpc-157-vs-tb-500) walks through the parent-protein question in more depth.

## What Does the Research Literature Study TB-500 For?

Published TB-500 research is preclinical — cell culture and animal models — and it centres on actin, the protein a cell assembles into its internal scaffolding. The fragment binds single, unassembled actin units, and that one property is why it was isolated at all.

- **Actin binding.** UniProt annotates thymosin beta-4 as binding and sequestering actin monomers, which holds back their assembly into filaments.
- **Blood-vessel formation assays.** A 2003 FASEB Journal study by Philp and colleagues reported that the seven-residue actin-binding motif was essential to the parent protein’s activity in angiogenesis assays, and that peptides missing any part of the motif were inactive.
- **Tissue-repair models.** The fragment also appears in animal models of tendon and soft-tissue injury, where it is studied alongside BPC-157.

The record stops at those model systems. TB-500 has not been approved as a medicine by any regulator, and the findings above describe what was measured in glassware and in animals, not an effect in a person.

## How Is TB-500 Tested?

TB-500 is tested with two complementary methods: high-performance liquid chromatography (HPLC), which reports how much of the sample runs as one peak, and mass spectrometry, which weighs the molecule to confirm which peptide is present.

_The two analytical methods used on TB-500 and what each one answers_

| Method | Question it answers | Why it matters for TB-500 |
| --- | --- | --- |
| HPLC | What share of the sample is a single component? | Shows whether the powder is mostly one peptide or a mixture of the target and its by-products |
| Mass spectrometry | Does the molecule weigh what the named peptide should? | Separates the sub-1 kDa fragment from the roughly 5 kDa parent protein, and catches a chain that has lost its acetyl cap |

The TB-500 that Australian Research Peptides lists carries the HPLC Verified grade: the material is analysed by a laboratory independent of both ARP and the manufacturer before it is released for sale. A result describes the batch that was analysed, not the product line in general.

No TB-500 certificate is on file in the [CoA library](https://www.australianresearchpeptides.au/coa) yet; reports are published there as they become available. [Peptide testing, purity and CoAs](https://www.australianresearchpeptides.au/articles/peptide-testing-purity-coa) explains how to read one line by line.

## How Is TB-500 Supplied in Australia?

Australian Research Peptides supplies TB-500 to laboratories and researchers in one strength, 10 mg, as freeze-dried powder under a tamper-evident seal, and posts it within Australia so a parcel never passes through customs.

The [TB-500 listing](https://www.australianresearchpeptides.au/products/tb-500) is out of stock at the moment, and it offers a single email alert for when a batch lands. The dry powder keeps best sealed, frozen and out of bright light until the day it is used. TB-500 is also one of the two peptides in [the BPC-157 + TB-500 blend](https://www.australianresearchpeptides.au/products/bpc-157-tb-500), which is a separate listing with its own batch record.

## Common Questions

### Where Can Laboratories Buy TB-500 in Australia?

Laboratories and researchers in Australia can buy TB-500 from Australian Research Peptides, which lists it as a single 10 mg freeze-dried vial and posts it domestically. The line is currently out of stock; its product page shows availability and takes a restock alert.

### Why Does TB-500 Have Several Spellings?

TB-500, TB500 and TB 500 are three spellings of one name for the same seven-amino-acid fragment. None of them is a different compound. The formal description is the N-terminally acetylated 17–23 fragment of thymosin beta-4.

### Can a Test Tell TB-500 From Thymosin Beta-4?

A mass spectrometry test can tell TB-500 from thymosin beta-4, because the fragment weighs under 1 kDa and the full protein about 5 kDa. The two cannot be confused on the instrument, whatever a label says.

Laboratories and researchers can order TB-500 from Australian Research Peptides as one freeze-dried vial in its Tissue Repair Research range, currently awaiting its next batch, posted within Australia from Sydney. For in vitro research purposes only.

## References

1. [UniProt P62328 (TYB4_HUMAN) — Thymosin beta-4, Homo sapiens.](https://www.uniprot.org/uniprotkb/P62328/entry)
2. [Philp D, Huff T, Gho YS, Hannappel E, Kleinman HK. The actin binding site on thymosin beta4 promotes angiogenesis. FASEB J. 2003 Nov;17(14):2103-5. PMID 14500546.](https://pubmed.ncbi.nlm.nih.gov/14500546/)
3. [PubChem CID 62707662 — TB-500 (National Library of Medicine).](https://pubchem.ncbi.nlm.nih.gov/compound/62707662)

## Related guides

- [Ipamorelin in Australia: What It Is and How It Is Tested](https://www.australianresearchpeptides.au/articles/ipamorelin-australia)
- [Beginner's Guide to Research Peptides](https://www.australianresearchpeptides.au/articles/research-peptides-beginners-guide)

## Related compounds

- [TB-500](https://www.australianresearchpeptides.au/products/tb-500)
- [BPC-157 + TB-500](https://www.australianresearchpeptides.au/products/bpc-157-tb-500)

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_All products supplied by Australian Research Peptides are for in vitro research purposes only._