Is TB-500 the same as thymosin beta-4?
Not necessarily, and the difference matters for any experiment.
- TB-500 as PubChem defines it is a short synthetic peptide: Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln, seven amino acids with an acetylated N-terminus (Ac-LKKTETQ). It corresponds to positions 17 to 23 of thymosin beta-4, which is why you will see it described as a thymosin beta-4 fragment.
- Thymosin beta-4 itself is a 43-amino-acid peptide with an acetylated N-terminus, about 4.96 kDa. Some suppliers sell this full-length molecule under the name "TB-500".
The two have very different masses (about 889 g/mol against about 4,963 g/mol), so a mass spectrum settles the question at once. Each batch's certificate states which one it is. Check any certificate's mass against the sequence with our peptide mass calculator.
Identity (TB-500 as the seven-residue peptide)
| Name | TB-500 (also TB500) |
| Sequence | Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH (Ac-LKKTETQ) |
| Length | 7 amino acids, N-terminally acetylated |
| Molecular formula | C₃₈H₆₈N₁₀O₁₄ |
| Molecular weight | 889.0 g/mol (monoisotopic mass 888.4916) |
| CAS number | 885340-08-9 |
Reference data from PubChem (CID 62707662); thymosin beta-4 data from UniProt (P62328). The batch certificate is the authority for the material you receive.
Specification and supply
| Strengths | 5 mg or 10 mg per vial |
| Pack | Box of 10 vials |
| Box codes | TB5 · TB10 |
| Form | Lyophilised (freeze-dried) powder |
| Availability | Pre-order, delivered within 14 days of confirmation. Currently in stock as part of the BPC-157 + TB-500 blend |
Documents and storage
Every batch ships with the manufacturer's certificate of analysis. Ask for the certificate of the current batch before you order. Safety data sheet: on request. Storage: as stated on the label. If you are unsure how to check a certificate, see how to read a certificate of analysis.
Calculated from the sequence
| Residues | 7 (Ac-LKKTETQ) |
| Approximate net charge at pH 7 | about 0 (two Lys, one Glu; acetylated N-terminus, free C-terminal acid) |
| Character | Close to neutral |
| Oxidation-prone residues | None of the easily oxidised residues (Cys, Met, Trp) |
These are estimates from the sequence, useful for planning laboratory work; the certificate of analysis reports the measured identity and purity of each batch.
Ordering for institutions
- Quotations within one working day, valid for 14 days, with lead time and delivery terms on one page.
- Invoices and documents in your institution's name; tell us if your purchase order needs to appear on them.
- Payment in full before dispatch, unless other terms are agreed in writing.
- Every shipment carries the batch number and expiry on the packing list and delivery note.
Who can buy it
Verified research buyers only, with a signed end-use declaration: laboratory research by qualified staff, no use in people or animals, no resale for those uses. We give no dosing or usage advice.
Related: BPC-157 · All research-grade products
Questions people ask
- Is TB-500 the same as thymosin beta-4?
The name is used for both. PubChem defines TB-500 as the acetylated seven-residue peptide Ac-LKKTETQ, part of thymosin beta-4; some suppliers use the name for full-length thymosin beta-4 (43 residues). Our certificates state which.
- What is the TB-500 amino acid sequence?
As PubChem defines it: Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH (Ac-LKKTETQ).
- What is the CAS number of TB-500?
885340-08-9 (PubChem, for the seven-residue peptide).
- What is the molecular weight of TB-500?
889.0 g/mol for Ac-LKKTETQ. Full-length thymosin beta-4 is about 4,963 g/mol.