TB-500 is the synthetic analogue of Thymosin Beta-4 — a naturally occurring 43-amino acid protein found in virtually all human and animal cells. As one of the most abundant intracellular peptides in the human body, Thymosin Beta-4 plays a fundamental role in actin regulation, cell migration, and tissue homeostasis. TB-500, its synthetic research counterpart, has become one of the most widely studied compounds in preclinical tissue repair research.
For researchers working in musculoskeletal repair, inflammation modulation, or regenerative biology, TB-500 offers a well-characterized molecular tool with a substantial and growing body of preclinical literature. This overview examines the compound’s molecular profile, primary research applications, and the quality considerations relevant to sourcing TB-500 for laboratory use.
TB-500 is a synthetic peptide analogue of Thymosin Beta-4 (Tβ4), specifically the actin-binding domain of the protein. While full-length Thymosin Beta-4 consists of 43 amino acids, TB-500 represents the key functional fragment — the sequence responsible for the protein’s primary biological interactions.
Thymosin Beta-4 was first isolated in the 1960s from thymus tissue and was initially studied in the context of immune function. Subsequent research identified its role as a G-actin sequestering protein — one that binds monomeric actin and regulates the dynamic equilibrium between filamentous (F-actin) and monomeric (G-actin) forms. This actin-regulatory function underlies many of Thymosin Beta-4’s observed biological effects, including its influence on cell migration, wound healing, and tissue repair.
TB-500 is supplied as a white lyophilized powder with a molecular weight of 4,963.44 g/mol — significantly larger than many research peptides, reflecting its 43-amino acid structure. It is water-soluble and reconstituted with sterile bacteriostatic water for research applications.
| Property | Value |
|---|---|
| Full name | TB-500 (Thymosin Beta-4 synthetic analogue) |
| Also known as | Tβ4, Thymosin Beta-4 fragment |
| Molecular formula | C212H350N56O78S |
| Molecular weight | 4,963.44 g/mol |
| CAS number | 77591-33-4 |
| Purity (Official Peptides) | >99% by HPLC |
| Physical form | White lyophilized powder |
| Solubility | Water soluble |
| Storage (lyophilized) | -20°C, protected from light |
| Storage (reconstituted) | 4°C, use within 30 days |
The foundational mechanism underlying TB-500’s research interest is its role as an actin-sequestering peptide. By binding G-actin (monomeric actin), Thymosin Beta-4 and its synthetic analogue regulate the pool of actin available for polymerization into F-actin filaments — a process fundamental to cell motility, division, and morphology.
This actin-regulatory function has broad implications for tissue repair research. Cell migration — a prerequisite for wound closure, immune cell recruitment, and tissue regeneration — depends on dynamic actin remodeling. Research examining TB-500’s effects on cell migration has documented increased migration rates in multiple cell types including endothelial cells, keratinocytes, and stem cells.
Studies examining wound closure models have observed accelerated epithelial migration in TB-500-treated samples, with researchers attributing this effect to the compound’s interaction with actin dynamics and its apparent influence on integrin expression — proteins responsible for cell-matrix adhesion during migration.
TB-500’s most extensively documented research application involves musculoskeletal tissue repair. Preclinical studies have examined the compound in models of muscle injury, tendon damage, ligament repair, and bone healing — with consistent findings of accelerated repair processes in treated groups.
Research examining TB-500 in muscle injury models has documented interactions with satellite cell activation — the muscle stem cells responsible for skeletal muscle regeneration. Studies have reported increased satellite cell proliferation and differentiation in TB-500-treated muscle injury models, suggesting a potential role in the early stages of muscle repair signaling.
Tendon and ligament research has examined TB-500’s effects on fibroblast activity, collagen synthesis, and extracellular matrix organization. Multiple studies have reported increased collagen production and improved structural organization of collagen fibers in treated tendon models — findings relevant to researchers studying the molecular basis of connective tissue repair.
One of the most actively investigated areas of TB-500 research involves cardiac tissue. Thymosin Beta-4 and its synthetic analogues have been studied extensively in cardiac repair models — an area of particular research interest given the limited regenerative capacity of adult cardiac tissue.
Seminal research published in Nature demonstrated that Thymosin Beta-4 could activate cardiac progenitor cells (epicardium-derived cells) in adult mouse hearts, promoting their migration and differentiation into cardiomyocytes. These findings prompted significant research interest in the compound’s potential interactions with cardiac regeneration pathways.
Subsequent studies have examined TB-500 in models of myocardial infarction, examining its effects on cardiomyocyte survival, angiogenesis in ischemic tissue, and cardiac fibrosis. Research has documented interactions with survival signaling pathways — including Akt and ILK (integrin-linked kinase) — in cardiac cell models, with treated groups showing reduced apoptotic signaling following ischemic challenge.
For researchers studying cardiac biology, TB-500 represents one of the few tool compounds with documented interactions specifically with cardiac progenitor cell activation — an area of significant translational research interest.
TB-500’s anti-inflammatory properties have been documented across multiple tissue types and inflammatory models. Research has examined its interactions with inflammatory cytokine expression, immune cell recruitment, and inflammatory signaling cascades.
Studies examining TB-500 in inflammatory models have reported reductions in pro-inflammatory cytokine expression — including TNF-α, IL-1β, and IL-6 — in treated groups. Research has also documented interactions with NF-κB signaling, a central regulator of inflammatory gene expression, with treated groups showing reduced NF-κB activation in response to inflammatory stimuli.
The compound’s apparent ability to modulate inflammation while simultaneously promoting repair processes makes it of particular interest to researchers studying the intersection of inflammation and tissue regeneration — a field that increasingly recognizes inflammation as a necessary but tightly regulated component of effective tissue repair.
TB-500’s interactions with angiogenesis — the formation of new blood vessels — represent another consistently documented research application. Studies have examined the compound’s effects on endothelial cell migration, tube formation, and VEGF expression in multiple model systems.
Research examining endothelial cell migration has documented significant increases in migration rates in TB-500-treated groups, with studies attributing this effect to the compound’s actin-regulatory properties — endothelial cell migration during angiogenesis requires dynamic actin remodeling. Tube formation assays have similarly reported enhanced angiogenic activity in treated groups.
These angiogenic properties are of particular relevance to researchers studying wound healing and ischemic tissue repair, where adequate vascularization is a rate-limiting factor in tissue recovery.
Understanding TB-500’s biology requires appreciation of the actin-thymosin system — the dynamic equilibrium between monomeric and filamentous actin that underlies cell motility and morphology.
In resting cells, approximately 50% of total actin exists in monomeric (G-actin) form, sequestered by binding proteins including Thymosin Beta-4. When cells receive signals to migrate or divide, this sequestered actin pool is rapidly mobilized for polymerization — a process regulated in part by the competition between Thymosin Beta-4 (which sequesters G-actin) and profilin (which promotes polymerization).
TB-500’s research utility derives partly from its ability to modulate this system. By influencing the availability of G-actin for polymerization, TB-500 can affect the dynamics of actin-dependent processes including cell migration, division, and morphological change — making it a valuable tool for researchers studying cytoskeletal biology and its downstream effects on tissue repair.
TB-500 and BPC-157 are frequently discussed together in tissue repair research contexts — and for good reason. Both are among the most studied tissue repair peptides in the preclinical literature, but they operate through distinct mechanisms and have different primary research applications.
TB-500 targets actin dynamics, cell migration, and cardiac-specific pathways. Its molecular weight (4,963.44 g/mol) is significantly larger than BPC-157, reflecting its 43-amino acid structure. Its primary research applications involve musculoskeletal repair, cardiac biology, and angiogenesis.
BPC-157 is a 15-amino acid gastric-derived peptide with primary research applications in tissue repair, GI biology, and neurological models. It operates through different signaling pathways — particularly growth factor signaling and NO system modulation.
Many research groups study both compounds simultaneously in repair models, examining potential complementary or synergistic interactions. For researchers designing experiments in tissue repair models, the choice between TB-500 and BPC-157 — or the decision to study both — depends on the specific pathways and endpoints of interest.
See our detailed BPC-157 vs TB-500 comparison guide for a full side-by-side analysis.
TB-500’s larger molecular size (relative to most research peptides) has implications for its handling and stability profile. As a 43-amino acid peptide, it is more susceptible to degradation from repeated freeze-thaw cycles than smaller peptides — making proper aliquoting particularly important.
Key research considerations for TB-500:
Reconstitution: TB-500 reconstitutes well in sterile bacteriostatic water. Some researchers prefer to add the solvent slowly to the lyophilized powder while gently swirling — avoiding vigorous agitation that can damage the peptide structure.
Aliquoting: Given TB-500’s susceptibility to freeze-thaw degradation, reconstituted solutions should be aliquoted into single-use volumes before storage at 4°C. This preserves compound integrity across the duration of an experiment.
Purity requirements: At >99% purity, TB-500 is supplied in a form suitable for sensitive biological assays. The compound’s larger molecular size means that impurities — even at low percentages — represent a greater absolute mass of contaminating material than in smaller peptides, reinforcing the importance of high-purity sourcing.
Concentration ranges: Published preclinical studies have used a wide range of TB-500 concentrations. Researchers should review the existing literature relevant to their specific model system to identify appropriate concentration ranges for their experimental design.
TB-500’s larger molecular weight and more complex synthesis requirements make it one of the more technically demanding research peptides to produce at high purity. This means that quality variation in the research supply market is significant — and that the consequences of sourcing substandard material are particularly pronounced.
For researchers whose experimental validity depends on compound purity and batch consistency, the sourcing decision for TB-500 warrants careful consideration.
Critical quality parameters for TB-500:
HPLC purity at >99% — Given the compound’s molecular complexity, HPLC purity verification is essential. Suppliers who cannot provide HPLC chromatograms for their TB-500 supply should not be considered for research applications.
Independent third-party COA — Manufacturer-provided quality documentation is insufficient for rigorous research. Independent laboratory verification — from an ISO-accredited analytical laboratory — provides the evidentiary standard that research requires.
Batch-specific documentation — TB-500 quality can vary between production batches. Batch-specific COA documentation allows researchers to assess the quality of their specific supply and identify any batch-to-batch variation that could affect experimental results.
Cold chain integrity — TB-500’s susceptibility to degradation makes shipping and storage conditions important. US-based supply eliminates the cold chain risks associated with international shipping and customs delays.
Official Peptides supplies TB-500 in 5mg and 10mg vials at >99% purity, independently verified by third-party HPLC analysis. Certificates of analysis are published for every production batch and accessible via the COA viewer on the TB-500 product page.
What is TB-500 used for in research?
TB-500 is studied in preclinical models examining musculoskeletal repair, cardiac tissue biology, angiogenesis, cell migration, and anti-inflammatory mechanisms. It is not approved for human use and is intended strictly for in vitro laboratory research.
How does TB-500 work at the molecular level?
TB-500 functions primarily as an actin-sequestering peptide, binding G-actin (monomeric actin) and regulating the dynamic equilibrium between monomeric and filamentous actin forms. This actin-regulatory function underlies its documented effects on cell migration, wound healing, and tissue repair processes.
What is the difference between TB-500 and Thymosin Beta-4?
Thymosin Beta-4 is the naturally occurring 43-amino acid protein. TB-500 is a synthetic analogue representing the key functional domain of Thymosin Beta-4 — the actin-binding sequence responsible for the protein’s primary biological interactions. For research purposes, TB-500 is the form available for laboratory supply.
What purity should research-grade TB-500 be?
For most research applications, >99% purity by HPLC is the appropriate standard. TB-500’s molecular complexity means that lower-purity preparations carry a greater risk of introducing confounding variables into sensitive biological assays.
How should TB-500 be stored?
Lyophilized TB-500 should be stored at -20°C protected from light and moisture. Once reconstituted, solutions should be aliquoted to avoid repeated freeze-thaw cycles and stored at 4°C for short-term use within 30 days.
Is a certificate of analysis available for Official Peptides TB-500?
Yes. Every batch of TB-500 supplied by Official Peptides is independently tested by a third-party analytical laboratory. Certificates of analysis are published and accessible via the COA viewer on the TB-500 product page.
TB-500 is among the most thoroughly studied tissue repair peptides in the preclinical research literature. Its documented interactions with actin dynamics, cell migration, musculoskeletal repair, cardiac biology, and angiogenesis make it a consistently valuable tool compound across a wide range of research applications.
For researchers sourcing TB-500, the compound’s molecular complexity reinforces the importance of high-purity supply with independent third-party verification. Batch-specific COA documentation from accredited laboratories is the appropriate evidentiary standard for research-grade peptide supply.
Official Peptides supplies TB-500 in 5mg and 10mg vials at >99% purity, with independent third-party HPLC verification and published certificates of analysis for every production batch.
→ View TB-500 product page and COA
This content is authored by Renata Voss, PhD, an independent research contributor specialising in peptide pharmacology and tissue repair biochemistry. All information is provided for research reference purposes only. TB-500 is not approved for human use and is not intended for diagnostic or therapeutic purposes. For in vitro laboratory research use only.
All content is provided for research reference purposes only. For in vitro laboratory research use only.