TB-500 5mg
Synthetic seven-residue research peptide corresponding to the actin-binding region of thymosin β4, supplied lyophilised for in-vitro laboratory use. Current released batch KB-26-0287 at 99.2% by RP-HPLC.
| Compound | TB-500 (thymosin β4 fragment, Tβ4 17-23) |
|---|---|
| CAS | 77591-33-4 |
| Sequence | Leu-Lys-Lys-Thr-Glu-Thr-Gln |
| Observed mass (ESI-MS) | 889.0 Da |
| Purity (RP-HPLC) | 99.2% · RT 6.18 min · C18, 214 nm |
| Presentation | Lyophilised white powder, sealed vial, 5mg (10mg also listed) |
| Storage | −20 °C sealed · 2–8 °C after reconstitution |
| Current batch | KB-26-0287, open certificate |
| Intended use | In-vitro laboratory research only · not for human or veterinary use |
TB-500 and thymosin β4 are not the same material
Thymosin β4 is a 43-amino-acid protein found in most mammalian tissues. TB-500 is a much shorter synthetic peptide covering a seven-residue actin-binding region within that sequence. Because the two differ substantially in molecular weight and hydrophobicity, they behave differently on a C18 column and are trivially distinguishable by mass spectrometry. If a supplier's certificate does not state which material was measured, that certificate cannot be interpreted.
How this batch was verified
Batch KB-26-0287 was separated by reverse-phase HPLC on a C18 column with UV detection at 214 nm. The analyte eluted at 6.18 minutes and integrated to 99.2% of total peak area. Identity was confirmed independently by ESI mass spectrometry against the expected 889.0 Da. Testing was carried out by Colmaric Analyticals on 2 April 2026, and the trace is published in full.
Handling and storage
- Store sealed at −20 °C, protected from light and moisture. Stable for 24 months from the test date.
- Bring to room temperature before opening to avoid condensation on the cake.
- Reconstitute with bacteriostatic water against the vial wall, not directly onto the powder.
- Refrigerate at 2–8 °C after reconstitution and use within 28 days. Avoid repeated freeze–thaw cycles.
Reference questions
What purity is Kelvin's TB-500?
Batch KB-26-0287 measured 99.2% by RP-HPLC on a C18 column at 214 nm, retention time 6.18 minutes, identity confirmed by ESI-MS against 889.0 Da. The release floor is 99.0%.
Is TB-500 sold for human use?
No. It is supplied strictly for in-vitro laboratory research and development, is not a medicine, food, supplement or cosmetic, and is not for human or veterinary use. Kelvin does not provide dosing or clinical guidance under any circumstances.
Where is the batch number printed?
On the vial label and on the outer seal. Enter it in the batch registry and the certificate and chromatogram load immediately.