Free 24-hour delivery over £75 · Same-day dispatchOrder before 3pm - same-day dispatch · Free 24-hour delivery over £75
Research use only
Kovalabs supplies research-grade peptides to qualified researchers for laboratory use only. They are not medicines, are not for human or animal consumption, and are supplied with no dosing or medical guidance.
You must be 18 or over and a qualified person purchasing solely for scientific research.
Selecting ‘I agree’ confirms the above and your acceptance of our Research Disclaimer and Terms of Sale.
· 8 min read
"TB-500" is a market name that gets used for two different materials, and the difference is worth knowing before you read any data sheet. Some suppliers sell a short seven-residue fragment under the name. Kovalabs supplies full-length synthetic thymosin beta-4 (TB-4): the complete 43-amino-acid, N-terminally acetylated peptide, about 4,963 g/mol. That matters for the literature too, because most published research attached to the TB-500 name was carried out on full-length thymosin beta-4, the same molecule we supply. Kovalabs supplies TB-500 strictly as a research reagent; everything below describes what published studies investigated, not any human use, benefit or outcome.
| Compound | TB-500 (full-length synthetic thymosin beta-4, TB-4) |
|---|---|
| Synonyms | Thymosin beta-4, TB-4, TB500, TB 500, timbetasin |
| Class | Synthetic N-acetylated 43-residue actin-binding peptide |
| Amino-acid sequence | Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES |
| Molecular formula | C212H350N56O78S |
| Molecular weight | 4,963.4 g/mol (average) |
| CAS number | 77591-33-4 |
| PubChem CID | 16132341 |
| Supply status | Research use only - not for human or veterinary use |
Thymosin beta-4 (PubChem CID 16132341, CAS 77591-33-4) is a 43-residue peptide, Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES, molecular formula C212H350N56O78S, average molecular weight about 4,963 g/mol. It carries an acetyl group on its N-terminal serine and contains no cysteine, so there is no disulfide bond to maintain. Kovalabs TB-500 is this full-length sequence, made synthetically. Every batch is tested by ILS Laboratories, an independent ISO/IEC 17025 lab, which confirms identity by HPLC against a thymosin beta-4 (TB-4) reference standard and reports purity and net peptide content. Each certificate carries an ILS access code that can be checked on the lab's own portal: see our certificates of analysis.
Across the market, the TB-500 name is used both for full-length thymosin beta-4 and for a seven-residue fragment, Ac-LKKTETQ (residues 17 to 23 of thymosin beta-4, about 889 g/mol), which corresponds to the actin-binding motif within the full sequence. They are different molecules and not interchangeable: the full-length peptide contains the complete 43-residue chain, including that motif, and is more than five times the mass of the fragment. Kovalabs supplies the full-length peptide, and the lot certificate of analysis confirms identity against a TB-4 reference standard.
| Property | Kovalabs TB-500 (full-length TB-4) | TB-500 fragment (other suppliers) |
|---|---|---|
| Residue count | 43 (complete sequence) | 7 |
| Sequence | Full 43-residue chain (contains the LKKTETQ actin-binding motif) | Ac-LKKTETQ |
| Molecular weight | ~4,963 g/mol | ~889 g/mol |
| CAS number | 77591-33-4 | Different record |
| Relationship | The complete peptide | A seven-residue excerpt of it |
| Supplied by Kovalabs | Yes | No |
The thymosin beta-4 mechanism that the structural literature actually resolves is actin handling. Full thymosin beta-4 is described as the principal intracellular sequestering peptide for monomeric (G-)actin, forming a 1:1 complex that holds actin in reserve and influences the monomer-to-filament equilibrium. Kovalabs TB-500 is that full-length peptide, so the mechanism literature below describes the same molecule. The biophysical characterisation is direct: De La Cruz et al. (Biophysical Journal, 2000; PMID 10777749) measured how thymosin beta-4 changes the conformation and dynamics of actin monomers in vitro. Review-level treatments of the beta-thymosin family and their actin interactions (Bubb, Vitam Horm 2003, PMID 12852258; Sun et al., Ann N Y Acad Sci 2007, PMID 17495248; Nachmias, Curr Opin Cell Biol 1993, PMID 8448031) situate the peptide in that cytoskeletal role. These describe a molecular mechanism; no human-relevant outcome is asserted from any of them.
The thymosin beta-4 literature is broad, and it concerns the full-length peptide, the same molecule Kovalabs supplies as TB-500. Each item below is stated as study design and the named topic or endpoint only. No result, effect size or benefit is reproduced.
The cited works are mechanism and review papers. No figures, regimens or results are reproduced from them here; this is research context, not a set of findings or instructions a reader should act on.
The notes below are general physicochemical and storage information for bench work only. They are not dosing, administration or use instructions, and nothing here describes a preparation for use in humans or animals.
TB-500 is typically supplied as a white lyophilised powder, commonly as the acetate salt. It is a hydrophilic, cysteine-free peptide that dissolves readily in aqueous laboratory solvents and has no disulfide bond to protect. Standard peptide practice applies: store the sealed lyophilate desiccated, cold and out of light, frozen for long-term storage, and equilibrate to room temperature before opening; reconstitute in an appropriate aqueous solvent and aliquot to avoid repeated freeze-thaw cycles. See the reconstitution guide. For identity, purity and net content on a specific lot, check the batch certificate of analysis against the lab's own portal. Researchers working across the tissue-repair set often cross-reference BPC-157 (the two are compared in the BPC-157 vs TB-500 reference) and the copper peptide GHK-Cu, within the tissue-repair research category.
The chemistry is settled: thymosin beta-4's identity, mass and sequence are well characterised, and its role as an actin-sequestering peptide is described directly in vitro (PMID 10777749), with the broader role surveyed in reviews. Because Kovalabs supplies the full-length peptide, that literature concerns the same molecule rather than a fragment of it. What it does not provide is human evidence: the work is mechanism, in-vitro characterisation and disease-context review. TB-500 is not a licensed medicine, and it has not been shown to produce defined outcomes in humans.
Kovalabs supplies TB-500 strictly as a research chemical for laboratory research use only. It is not a medicine, supplement or veterinary product, is not for human or veterinary use, and nothing on this page constitutes a medicinal, therapeutic, healing, efficacy, dosing or human-outcome claim. It has not been evaluated by the MHRA or any comparable regulator for safety or efficacy in humans or animals. The descriptions above are restricted to chemistry and to study designs and named topics, stated only as what each study investigated. Every batch is third-party tested with a certificate of analysis. Purchasers are responsible for handling, storing and using the material in compliance with all applicable laws and institutional requirements. Full terms are on the research disclaimer page.
At Kovalabs, yes. Our TB-500 is full-length synthetic thymosin beta-4 (TB-4): the complete 43-residue peptide, about 4,963 g/mol, CAS 77591-33-4. Across the market the TB-500 name is also used for a seven-residue fragment, Ac-LKKTETQ (about 889 g/mol), which is a different molecule. Our certificates of analysis confirm identity against a TB-4 reference standard.
PubChem CID 16132341, CAS 77591-33-4, molecular formula C212H350N56O78S, average molecular weight about 4,963 g/mol, 43 residues, sequence Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES (N-terminally acetylated).
Actin handling. Thymosin beta-4 is described as the principal intracellular sequestering peptide for monomeric G-actin, and in-vitro biophysics has measured how it changes actin-monomer conformation and dynamics (PMID 10777749). This is a molecular mechanism described in the literature, not a statement of any effect in humans or animals.
As bench handling of a research reagent only. The lyophilised powder is stored sealed, desiccated, cold and out of light (frozen for long-term storage) and equilibrated to room temperature before opening. It is a hydrophilic, cysteine-free peptide, so it dissolves readily in an appropriate aqueous laboratory solvent; aliquot to avoid freeze-thaw cycles. See the reconstitution guide. None of this is a preparation method for any use in humans or animals.
The publication titles below are the original authors' own titles, reproduced so each citation can be verified against PubMed and the cited DOI. They are not statements, conclusions or claims by Kovalabs, and the body of this page describes each study by its design and named topic only.