What Is TB-500?
TB-500 is a synthetic version of Thymosin Beta-4 (Tβ4), a naturally occurring 43-amino-acid protein involved in angiogenesis, muscle regeneration, wound repair, and cardiac protection in preclinical research.
TB-500 is a synthetic peptide analogue corresponding to the actin-binding active region of Thymosin Beta-4 (Tβ4), a naturally occurring 43 amino acid protein expressed ubiquitously in mammalian cells. Thymosin Beta-4 was originally isolated from thymic tissue during a systematic investigation of thymic peptide fractions in the 1960s and 1970s. The full-length protein is among the most abundant intracellular peptides in many cell types, where it plays an indispensable role in regulating the dynamics of the actin cytoskeleton — the fundamental scaffold governing cell shape, motility, and division.
The "TB-500" designation is commonly used in research settings to refer to the synthetic version of the LKKTETQ heptapeptide sequence corresponding to the actin-binding domain (residues 17–23) of the full Thymosin Beta-4 molecule. Research has demonstrated that this fragment retains substantial biological activity comparable to the complete protein in many in vitro and animal model assays. This has made TB-500 a cost-effective and accessible tool for preclinical research applications compared to working with the full recombinant protein.
The scientific literature on Thymosin Beta-4 and its analogues is extensive, spanning cardiac repair, ocular wound healing, central nervous system protection, skin wound healing, and musculoskeletal tissue recovery. Studies by Dr. Hynda Kleinman at the NIH and collaborators have been particularly significant in establishing the mechanistic basis for Tβ4's pro-angiogenic and anti-inflammatory activities. TB-500 research compounds from Rainbow Peptide are provided exclusively for licensed research use. They are not approved for or intended for human administration under any circumstances.
Mechanism of Action
TB-500 / Thymosin Beta-4 acts primarily by sequestering G-actin to promote cell migration, upregulating the PI3K/Akt survival pathway, stimulating VEGF-mediated angiogenesis, and reducing inflammatory cytokines at injury sites.
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G-Actin Sequestration and Cytoskeletal Regulation TB-500's primary biochemical role is sequestration of monomeric globular actin (G-actin). By binding G-actin with high affinity, TB-500 modulates the equilibrium between G-actin and filamentous F-actin, influencing cytoskeletal dynamics critical for cell migration. This mechanism is particularly relevant to wound-edge fibroblast and keratinocyte mobilisation in healing tissue research models.
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Anti-Inflammatory Cytokine Downregulation Research demonstrates TB-500 / Tβ4 suppresses inflammatory mediators including TNF-α, IL-1β, and IL-6 in macrophage and cardiac fibroblast models. The anti-inflammatory effect is proposed to involve NF-κB pathway modulation, reducing leukocyte infiltration scores in acute injury animal models — a profile distinct from steroid-based anti-inflammatory compounds.
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Angiogenesis via Integrin Signalling Tβ4 interacts with integrin-linked kinase (ILK), activating downstream AKT and VEGF signalling. In corneal and dermal wound models, this pathway promotes endothelial cell sprouting and microvascular network formation. The pro-angiogenic effect appears dependent on an intact ILK interaction domain — a mechanistic target for ongoing molecular research.
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Cardiac Progenitor Cell Activation Post-myocardial infarction studies in rodent models have demonstrated Tβ4 pretreatment activates cardiac progenitor cells and reduces scar size. The proposed mechanism involves epicardial EMT (epithelial-mesenchymal transition) induction and activation of cardiomyocyte survival pathways. This cardiac research dimension represents one of the more advanced translational research areas for this compound class.
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Stem Cell Chemoattraction TB-500 / Tβ4 has demonstrated chemotactic activity in stem cell migration assays, attracting mesenchymal stem cells (MSCs) toward wound sites in vitro. This chemoattraction is proposed to amplify endogenous repair responses by recruiting repair-competent progenitor populations to sites of tissue damage — an area of active investigation in regenerative medicine research.
Reconstitution Reference
The following reference is provided for licensed research professionals only. All reconstitution and handling must comply with your institution's biosafety protocols.
| Vial Size | BAC Water Volume | Resulting Concentration | Storage | Peptide Calculator |
| 5 mg | 2.0 mL | 2,500 mcg/mL | 2–8°C after reconstitution | Calculate Dose → |
| 10 mg | 4.0 mL | 2,500 mcg/mL | 2–8°C after reconstitution | Calculate Dose → |
TB-500 lyophilised powder is stable at -20°C for up to 24 months when protected from moisture and light. Reconstituted solutions should be used within 28 days. Handle using aseptic technique under appropriate laboratory conditions.
Competitive Pricing Comparison
Market price data from independent competitor analysis. All products are For Research Use Only.
| Supplier | Price Range (per vial) | Avg Market Price | COA Available |
| Competitor Low | $62 | — | Varies |
| Competitor High | $136 | — | Varies |
| Market Average | — | $92 | — |
| Rainbow Peptide | View Price → | ✓ Yes — HPLC + MS |
Published Research References
Studies cited for scientific reference. All data from preclinical or in vitro models unless stated. Not medical advice.
- Goldstein AL, Kleinman HK. "Advances in the basic and clinical applications of thymosin β4." Expert Opin Biol Ther. 2015;15(S1):S139–145. PubMed 22909189 ↗
- Bock-Marquette I, et al. "Thymosin β4 activates integrin-linked kinase and promotes cardiac cell migration, survival and cardiac repair." Nature. 2004;432:466–472. PubMed 15290252 ↗
- Smart N, et al. "Thymosin β4 induces adult epicardial progenitor mobilization and neovascularization." Nature. 2007;445:177–182. PubMed 17522624 ↗
- Huff T, et al. "Beta-thymosins, small acidic peptides with multiple functions." Int J Biochem Cell Biol. 2001;33(3):205–220. PubMed 11311852 ↗