TB-500 5mg
Synthetic seven-residue peptide corresponding to the actin-binding region of thymosin β4, supplied lyophilised for in-vitro laboratory use. Observed mass 889.0 Da, released against a not-less-than 99.0 per cent purity specification.
Specification
| Compound | TB-500 (thymosin β4 fragment, Tβ4 17–23) |
|---|---|
| CAS | 77591-33-4 |
| Sequence | Leu-Lys-Lys-Thr-Glu-Thr-Gln |
| Residues | 7 |
| Observed mass | 889.0 Da · ESI-MS, positive mode |
| Purity specification | NLT 99.0% main-peak area · RP-HPLC C18, 214 nm |
| Batch result | 99.2% · RT 6.18 min |
| Presentation | Lyophilised white cake, sealed vial, 5mg (10mg also listed) |
| Storage | −20 °C sealed · 2–8 °C reconstituted |
| Certificate | IF-26-4402, open the record |
| Intended use | In-vitro laboratory research only · not for human or veterinary use |
TB-500 is not thymosin β4
Thymosin β4 is a forty-three-amino-acid protein present in most mammalian tissues. TB-500 is a much shorter synthetic peptide covering a seven-residue actin-binding region within that sequence. The two differ substantially in molecular weight and hydrophobicity, so they behave differently on a C18 column and are trivially distinguishable by mass spectrometry. A certificate that does not state which material was measured cannot be interpreted, which is why the observed mass sits next to the purity figure on every Isoform record rather than behind it.
How this batch cleared release
Identity first: ESI mass spectrometry returned 889.0 Da against the calculated value. Purity second: separation on C18 with detection at 214 nm, eluting at 6.18 minutes and integrating to 99.2 per cent of total peak area. Analysis by Colmaric Analyticals on 2 April 2026, published in full against the batch number.
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
What is the purity specification?
Not less than 99.0 per cent main-peak area by RP-HPLC on C18 at 214 nm. Batch IF-26-4402 measured 99.2 per cent at a retention time of 6.18 minutes, identity confirmed by ESI-MS against 889.0 Da.
Is TB-500 sold for human use?
No. Supplied strictly for in-vitro laboratory research and development, not a medicine, food, supplement or cosmetic, and not for human or veterinary use. Isoform 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. Type it into the retrieval field on the homepage and the certificate loads immediately.