Maple TB-500 is a synthetic fragment of thymosin beta-4 (Tβ4), a 43-amino acid naturally occurring peptide present in nearly all mammalian cell types except red blood cells. Thymosin beta-4 is the primary intracellular G-actin sequestering peptide in most vertebrate cells, playing a central role in actin cytoskeleton dynamics, cell migration, and tissue repair signaling. TB-500 replicates the active region of the full-length Tβ4 molecule and is widely used in preclinical research.
For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.
Molecular Profile
Thymosin beta-4, the parent molecule from which TB-500 is derived, has the molecular formula C212H350N56O78S with a molecular weight of approximately 4963.5 Da and CAS number 77591-33-4. The peptide was originally isolated from thymic tissue in the 1960s by Allan Goldstein’s research group, initially characterized as a thymic hormone before its primary function as an actin-sequestering peptide was identified by Safer et al. in 1990 (Hannappel, Annals of the New York Academy of Sciences, 2007, DOI: 10.1196/annals.1415.018).
TB-500 specifically encompasses the actin-binding domain of Tβ4, centered around the amino acid sequence LKKTETQ (residues 17-23 of the full molecule). This seven-amino acid region has been demonstrated to independently reproduce several of the biological activities attributed to the full-length peptide, including promotion of dermal wound repair in both diabetic and aged mouse models (Philp et al., Wound Repair and Regeneration, 2003, DOI: 10.1046/j.1524-475x.2003.11105.x).
Primary Research Mechanisms
Actin Cytoskeleton Regulation
The most thoroughly characterized mechanism of thymosin beta-4 involves its interaction with monomeric globular actin (G-actin). Tβ4 binds G-actin with a dissociation constant in the micromolar range, sequestering actin monomers and regulating the pool of unpolymerized actin available for filament assembly. This rapid binding and release dynamic positions Tβ4 as a central regulator of cytoskeletal reorganization, which underlies cell motility, division, and morphological adaptation (Hannappel, 2007).
The peptide is present in both the cytoplasm and nucleus, suggesting roles in both cytoplasmic cytoskeletal dynamics and nuclear actin functions. In the context of tissue injury, actin regulation directly influences cell migration to wound sites, a prerequisite for effective repair across all tissue types.
Wound Healing and Tissue Repair
According to research indexed in PubMed, thymosin beta-4 promotes tissue repair through multiple coordinated mechanisms. A comprehensive review by Goldstein et al. (2012) in Expert Opinion on Biological Therapy (DOI: 10.1517/14712598.2012.634793) described Tβ4 as a “multi-functional regenerative peptide” that, after injury, is released by platelets, macrophages, and other cell types to protect cells and tissues from further damage. The review identified several distinct repair-related activities: promotion of cell migration including mobilization and differentiation of stem/progenitor cells, stimulation of new blood vessel formation (angiogenesis), reduction of apoptosis, suppression of inflammation, and decrease in myofibroblast numbers resulting in reduced scar formation and fibrosis.
In dermal wound models, Philp et al. (2003) at the National Institutes of Health demonstrated that thymosin beta-4 accelerated wound repair in both db/db diabetic mice and aged mice (26 months old), two models characterized by significantly impaired healing. In the diabetic model, wound contracture and collagen deposition were significantly increased with Tβ4 treatment. In the aged model, Tβ4 improved keratinocyte migration, wound contracture, and collagen deposition. Notably, the synthetic seven-amino acid actin-binding domain peptide (LKKTETQ) was able to promote repair in aged animals at levels comparable to the full-length molecule.
Anti-inflammatory Properties
Research in corneal wound models has characterized thymosin beta-4’s anti-inflammatory activity. Sosne et al. (2007) reported that Tβ4 suppresses inflammation through modulation of inflammatory cytokine and chemokine expression. In corneal injury models, Tβ4 treatment reduced inflammatory cell infiltration while simultaneously promoting epithelial cell migration and wound closure. This dual anti-inflammatory and pro-migratory activity distinguishes Tβ4 from many anti-inflammatory agents that suppress healing alongside inflammation.
Angiogenesis
Thymosin beta-4 promotes the formation of new blood vessels from pre-existing vasculature. In preclinical cardiac models, Tβ4 treatment following ischemic injury promoted neovascularization in the peri-infarct zone. The angiogenic mechanism involves promotion of endothelial cell migration and tube formation, which are actin-dependent processes directly influenced by Tβ4’s cytoskeletal regulatory function. This vascular formation capacity has made Tβ4 a subject of particular interest in research on tissue types with limited vascular supply, where poor perfusion is a primary barrier to repair.
Research Applications by Tissue Type
Preclinical research on thymosin beta-4 spans multiple organ systems. Goldstein et al. (2012) outlined the therapeutic evaluation of Tβ4 across skin (dermal wounds, burns, chronic ulcers), eye (corneal epithelial wounds, dry eye, chemical burns), heart (post-myocardial infarction repair, activation of epicardial progenitor cells), and brain (traumatic brain injury, stroke, multiple sclerosis models). In each tissue context, the peptide’s mechanism converges on the same core activities: cell migration, angiogenesis, anti-inflammation, and anti-fibrosis.
The kidney research by Vasilopoulou et al. (2016) at UCL Institute of Child Health (DOI: 10.1016/j.kint.2016.06.032) demonstrated that endogenous Tβ4 is prominently expressed in podocytes of developing and adult mouse glomeruli, and that loss of Tβ4 accelerated the severity of immune-mediated glomerular disease with worse renal function, periglomerular inflammation, and fibrosis. This loss-of-function study provided evidence that endogenous Tβ4 acts as a protective modifier of injury, functioning as a brake to slow disease progression.
Safety Profile
Thymosin beta-4 is an endogenous peptide present in high concentrations in most mammalian cells (typical intracellular concentrations range from 0.1 to 0.5 mM). Preclinical toxicology studies and early-phase clinical trials for corneal wound healing (conducted by RegeneRx Biopharmaceuticals) have not identified significant adverse effects at therapeutic doses. The peptide’s endogenous origin and ubiquitous cellular distribution contribute to its favorable safety profile in preclinical models.
TB-500 has not been approved by the FDA, Health Canada, or other regulatory authorities for human therapeutic use. It is listed as a prohibited substance by the World Anti-Doping Agency (WADA) and the Federation Equestre Internationale (FEI).
Product Specifications
CAS Number: 77591-33-4 (thymosin beta-4)
Molecular Formula: C212H350N56O78S
Molecular Weight: ~4963.5 Da
Purity: ≥99% (HPLC verified)
Form: Lyophilized powder
Storage: -20°C, desiccated, protected from light
COA: Batch-specific Certificate of Analysis by independent third-party testing (Testides Analytical)
View TB-500 5mg Product Page | View TB-500 10mg Product Page
Frequently Asked Questions
What is TB-500 and how does it relate to thymosin beta-4?
TB-500 is a synthetic peptide fragment corresponding to the active region of thymosin beta-4 (Tβ4), a naturally occurring 43-amino acid peptide found in nearly all mammalian cells. The active region of TB-500 centers on the actin-binding domain sequence LKKTETQ (residues 17-23), which research has shown can independently reproduce key biological activities of the full-length molecule, including promotion of cell migration and wound repair in preclinical models.
What is the primary mechanism of thymosin beta-4?
The primary characterized mechanism of thymosin beta-4 is G-actin sequestration. Tβ4 binds monomeric actin with micromolar affinity, regulating the pool of unpolymerized actin available for cytoskeletal assembly. This actin regulation directly governs cell migration, morphological adaptation, and tissue repair processes. Beyond actin binding, Tβ4 has been documented to promote angiogenesis, reduce inflammation, suppress apoptosis, and decrease fibrosis in preclinical models, though the molecular pathways linking these diverse activities are still being characterized.
Where can I buy TB-500 research peptide in Canada?
Maple Research Labs supplies TB-500 in 5mg and 10mg vial sizes. All TB-500 ships from within Canada with same-day processing and includes a batch-specific Certificate of Analysis verified by Testides Analytical. TB-500 is sold exclusively for research purposes and is not approved for human use.
How does TB-500 compare to BPC-157 in research?
TB-500 and BPC-157 are both studied in preclinical tissue repair models but operate through distinct mechanisms. TB-500 acts primarily through actin cytoskeleton regulation and is an endogenous peptide found in nearly all cells. BPC-157 acts through angiogenic growth factor modulation and the nitric oxide system, and is derived from human gastric juice. Both peptides promote cell migration and angiogenesis in animal models, but through different molecular pathways. Maple Research Labs also offers a BPC-157 + TB-500 blend for researchers studying combined effects. For a detailed comparison, see our BPC-157 vs TB-500 Research Comparison.
Related Research
Explore related peptide research from Maple Research Labs: BPC-157 Pentadecapeptide | BPC-157 + TB-500 Blend | GHK-Cu Copper Peptide | BPC-157 vs TB-500 Comparison | Understanding Certificates of Analysis
For research purposes only. Not for human consumption. Not for diagnostic or therapeutic use.