TB-500 — Compound Overview
A researcher-focused overview of TB-500: its relationship to thymosin beta-4, its chemistry, the research literature around it, and how each batch is documented.
Last updated: 2026-08-21 · By: Index Peptides technical team
Key facts about TB-500
| Compound | TB-500 |
|---|---|
| CAS number | 885340-08-9 |
| Molecular formula | C38H68N10O14 |
| Molecular weight | 889.0 g/mol |
| Sequence | Ac-LKKTETQ (Tβ4 17–23) |
| Listed formats | 10mg per vial, 20mg per vial, 70mg per vial |
| Intended use | In-vitro laboratory research only |
What is TB-500?
TB-500 is a synthetic peptide corresponding to the actin-binding segment of thymosin beta-4 (Tβ4), a 43-amino-acid protein found in most mammalian cells. The commonly supplied research fragment is the acetylated heptapeptide LKKTETQ (residues 17–23 of Tβ4). TB-500 is produced synthetically and is chemically distinct from full-length thymosin beta-4, although the two names are often conflated in informal sources.
Chemistry and structure
The TB-500 fragment carries CAS registry number 885340-08-9, molecular formula C38H68N10O14 and a molecular weight of approximately 889.0 g/mol. The N-terminal acetyl group mimics the corresponding region of the parent protein. The certificate of analysis for each batch records the exact form and counter-ion tested.
TB-500 in the research literature
Thymosin beta-4 — the parent protein — is one of the major actin-sequestering molecules in mammalian cells and has an extensive preclinical literature covering actin dynamics, cell migration and tissue models. The LKKTETQ fragment is studied specifically as the actin-binding motif of that protein. As with most research peptides, the literature is preclinical; controlled human data for the synthetic fragment are lacking.
Regulatory status
TB-500 is not an approved medicine in any jurisdiction and is prohibited in sport by WADA. Index Peptides supplies it strictly for in-vitro laboratory research — not for human or veterinary use.
Form, handling and storage
Supplied as a lyophilised powder in a sealed vial. Store at -20°C, desiccated and protected from light, per the batch record. Handling is the responsibility of the qualified researcher.
Batch documentation at Index Peptides
Review the published certificate for the exact lot, including the laboratory, report date and analytical results actually reported. HPLC purity alone does not confirm LC-MS identity. Contact us before ordering if a required result is not published.
Frequently asked questions
Is TB-500 the same as thymosin beta-4?
No. TB-500 is a short synthetic fragment (residues 17–23) of the 43-amino-acid thymosin beta-4 protein. Listings that use the names interchangeably are imprecise — the certificate of analysis states exactly what is in the vial.
Is TB-500 approved for human use?
No. It is not an approved medicine anywhere and is supplied strictly for in-vitro laboratory research.
How is each batch verified?
Reversed-phase HPLC for purity and LC-MS for identity, with the COA published on the product page and batch lookup by lot number.
How do I reconstitute TB-500?
Reconstitution is a laboratory handling procedure, not a use instruction. Our documentation-led reconstitution guide covers the mechanics of dissolving lyophilised peptide powders: https://indexpeptides.uk/guides/peptide-reconstitution-guide. Handling is the responsibility of the qualified researcher.
What is the shelf life of TB-500?
As supplied (lyophilised powder in a sealed vial), TB-500 is stored at -20C, desiccated and protected from light. Long-term stability is documented per batch on the certificate of analysis; treat the batch record as the authoritative shelf-life reference for that lot.
What is the difference between the sizes?
The difference is the nominal peptide content per vial. TB-500 is supplied as 10mg single-compound vials, plus blend vials. Every format carries the same batch documentation and purity testing.
What does the certificate of analysis show?
Review the published certificate for the exact lot, including the laboratory, report date and analytical results actually reported. HPLC purity alone does not confirm LC-MS identity. Contact us before ordering if a required result is not published.
How does TB-500 compare with BPC-157?
See our comparison of TB-500 vs BPC-157: https://indexpeptides.uk/guides/bpc-157-vs-tb-500
References
Research use only. Not for human or animal consumption.