TB-500

Synthetic Thymosin Beta-4 fragment · 17-residue peptide

Identifier graph

Cross-references to canonical chemistry knowledge graphs. Each binding is the same identity used in PubMed-indexed literature.

CAS Registry Number
885340-08-9 · CAS Common Chemistry
InChIKey
ADKDNDYYIZUVCZ-ZQNQAVPYSA-N
PubChem CID
CID 62707662
Molecular weight
~887 g/mol
IUPAC name
(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-acetamido-4-methylpentanoyl]amino]-6-aminohexanoyl]amino]-6-aminohexanoyl]amino]-3-hydroxybutanoyl]amino]-4-carboxybutanoyl]amino]-3-hydroxybutanoyl]amino]-5-amino-5-oxopentanoic acid

What is TB-500?

TB-500 is a synthetic peptide corresponding to the 17-residue active site (residues 17–23) of the parent protein Thymosin Beta-4 (TβTB-4) — a 44-residue actin-binding peptide that is ubiquitously expressed in mammalian tissues. The fragment retains the actin-binding domain responsible for the regenerative activity attributed to the full protein, while being synthetically more accessible and pharmacokinetically better-defined for laboratory research.

TB-500 is supplied as a lyophilised acetate salt with the observed sequence Ac-Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys- Phe-Asp-Lys-Ser-Lys-Leu (the N-terminal serine is acetylated to mirror the natural maturation of Thymosin Beta-4). Approximate molecular weight is 1888 Da depending on counterion content.

Mechanism of action

The primary published mechanism is sequestration of monomeric G-actin, which alters the kinetics of actin-filament assembly and disassembly in cells migrating into wound sites. By keeping a larger pool of G-actin available, TB-500 (and the parent TβTB-4) appears to facilitate the cellular cytoskeletal rearrangements required for cell motility, differentiation decisions in endothelial precursors, and the recruitment of progenitor cells to sites of injury.

Secondary mechanisms reported in the literature include suppression of NF-κB-driven inflammatory signalling and promotion of angiogenesis through interactions with vascular endothelial growth factor pathways.

Research context

Investigated in preclinical models of cardiac infarct repair, corneal wound healing, ligament transection recovery and dermal wound closure. The 17-residue fragment is often selected over the full 44-residue parent because synthesis cost is lower and the active site is conserved. In tissue-repair research, TB-500 is frequently paired with BPC-157 in combination-effect studies.

Analytical specifications

Every batch of TB-500 supplied by NMChem is characterised by reversed-phase HPLC for purity determination and by mass spectrometry for identity confirmation. Certificate of Analysis (COA) documents are issued per batch and made available on request.

Identity is confirmed by electrospray-ionisation mass spectrometry (ESI-MS); the observed mass falls within ±2 Da of the theoretical monoisotopic mass calculated from the residue sequence. Purity is determined by reversed-phase HPLC on a C18 column with a trifluoroacetic-acid-modified water/acetonitrile gradient and reported as the area-under-curve percentage of the main peak at 214 nm. NMChem specification is ≥99% main peak. Material ships as lyophilised powder and must be reconstituted in sterile water or bacteriostatic water immediately before use.

Browse the COA database

UK regulatory status

Supplied as a research-grade reference standard for laboratory use only. Not a licensed medicinal product in the United Kingdom and not approved by the MHRA for human or veterinary administration. Sale is restricted to researchers, institutions and laboratory professionals; the compound must be retained within research premises. End-user compliance with the Human Medicines Regulations 2012, the Misuse of Drugs Act 1971 (where applicable) and local institutional biosafety policy is the responsibility of the buyer.

Research literature

Selected peer-reviewed publications from PubMed referencing this compound.

  1. Simultaneous quantification of TB-500 and its metabolites in in-vitro experiments and rats by UHPLC-Q-Exactive orbitrap MS/MS and their screening by wound healing activities in-vitro. Rahaman KA et al. · Journal of chromatography. B, Analytical technologies in the biomedical and life sciences · 2024
    PubMed PMID 38382158
  2. Therapeutic Peptides in Orthopaedics: Applications, Challenges, and Future Directions. Rahman OF et al. · Journal of the American Academy of Orthopaedic Surgeons. Global research & reviews · 2026
    PubMed PMID 41490200
  3. Injectable Peptide Therapy: A Primer for Orthopaedic and Sports Medicine Physicians. Mayfield CK et al. · The American journal of sports medicine · 2026
    PubMed PMID 41476424

Related compounds

Other research compounds in adjacent mechanism classes or commonly used alongside TB-500.

  • BPC-157
    Pentadecapeptide · cytoprotective fragment
  • GHK-Cu
    Tripeptide-copper complex · regenerative peptide
  • AHK-Cu
    Tripeptide-copper complex · regenerative peptide

Frequently asked questions about TB-500

What is the difference between TB-500 and Thymosin Beta-4?
Thymosin Beta-4 is the full 44-residue parent protein. TB-500 is a synthetic 17-residue fragment corresponding to residues 17–23 of TβTB-4 — the active actin-binding domain. The fragment retains the regenerative activity attributed to the parent protein while being more accessible synthetically.
What is the molecular weight of TB-500?
Approximately 1888 Da depending on counterion content (TB-500 is typically supplied as the acetate salt). The published CAS Registry Number is 885340-08-9.
Is TB-500 approved for clinical use?
No. TB-500 has no approved therapeutic indication and is not a licensed medicinal product in the UK or any other jurisdiction. It is supplied as a research-grade reference standard for laboratory and preclinical use only.

Get research-grade TB-500 from NMChem

UK supplier · HPLC and MS verified · Per-batch Certificate of Analysis · Tracked Royal Mail dispatch.

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