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What Is TB-500? Complete Thymosin Beta 4 Fragment Research Peptide Guide
What is TB-500? TB-500 is a synthetic 17-amino acid peptide fragment derived from the actin-binding domain of Thymosin Beta 4 (TB4), a 43-amino acid intracellular protein found in nearly all mammalian cells. The defining biological property of TB-500 is its ability to bind monomeric G-actin and sequester it from the actin polymerisation pathway. This reflects the actin-binding activity associated with the parent Thymosin Beta 4 protein, but in a smaller and more analytically tractable peptide format. TB-500 is one of the most extensively studied research peptides in published in-vitro literature in published in-vitro literature and is frequently paired with BPC-157 in combined recovery research protocols where mechanistic independence between the two compounds is the analytical foundation.
TB-500 is supplied for in-vitro laboratory research only. It is not a licensed medicinal product under the UK Human Medicines Regulations 2012, and no dosing or administration guidelines are provided in this guide or in any Ascend Peptides UK documentation. The compound is supplied to qualified research professionals (laboratories, academic institutions, research scientists) for in vitro cellular research applications. Every batch of TB-500 supplied by Ascend Peptides UK is HPLC verified at ≥98% purity by Janoshik laboratory, LC-MS confirmed for molecular identity, and accompanied by a publicly verifiable Certificate of Analysis.
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What Is TB-500 at the Molecular Level?
TB-500 is a synthetic 17-amino acid peptide corresponding to a specific fragment of the parent Thymosin Beta 4 (TB4) protein. The fragment contains the actin-binding domain of TB4, which is the functional region responsible for the biological activity of the full-length protein. The compound is supplied to laboratories as a lyophilised (freeze-dried) white powder for reconstitution before in-vitro research use. The molecular structure and key chemical properties of TB-500 are documented below.
|
Molecular Property |
Value |
|---|---|
|
Compound name |
TB-500 (Thymosin Beta 4 Fragment) |
|
Peptide class |
17 amino acid peptide fragment |
|
Source protein |
Thymosin Beta 4 (TB4, 43 amino acid native protein) |
|
Functional domain |
Actin-binding domain (corresponds to TB4 residues 17-23 and surrounding sequence) |
|
Molecular formula |
C212H350N56O78S |
|
Molecular weight |
≈ 4963.44 Da |
|
Key binding partner |
Monomeric G-actin (cytoskeletal protein) |
|
Supplied format |
Lyophilised white powder for reconstitution |
|
Storage |
−20°C lyophilised, 2 to 8°C reconstituted |
Two structural properties define TB-500 in the research peptide category. First, it is one of the larger compounds in the standard research peptide range, at 17 amino acids and approximately 4963 Da molecular weight. This makes TB-500 substantially larger than typical short peptides (such as Ipamorelin at 5 amino acids, or GHK-Cu at 3 amino acids) but smaller than full protein fragments. Second, TB-500 includes the specific actin-binding sequence motif from the parent Thymosin Beta 4 protein, which is the functional region responsible for G-actin sequestration activity. This sequence specificity is what distinguishes TB-500 from arbitrary peptide fragments of TB4 and is the reason TB-500 retains the actin-binding biological property of the parent protein.
The full molecular identity of TB-500 is confirmed on every Ascend Peptides UK batch by independent LC-MS analysis through Janoshik laboratory. The measured molecular weight is matched against the theoretical molecular weight (≈ 4963.44 Da) to confirm structural identity. The substantial molecular size of TB-500 makes accurate LC-MS verification particularly important, since smaller substituted peptide fragments would have significantly lower molecular weights detectable as a clear mismatch. The complete laboratory quality control workflow is documented on the how we test peptides page.
How Does TB-500 Work in Cellular Research Models?
TB-500 acts through actin sequestration. The compound binds monomeric G-actin (the soluble globular form of the actin protein) and prevents it from polymerising into F-actin (the filamentous structural form that makes up the cellular cytoskeleton). The actin polymerisation balance between G-actin and F-actin is a fundamental cellular regulatory mechanism affecting cell shape, cell migration, and many downstream cytoskeletal processes. By sequestering G-actin, TB-500 shifts this balance and influences cellular processes that depend on actin polymerisation dynamics.
The G-actin Sequestration Mechanism
The actin sequestration pathway works in research models as follows:
-
Native G-actin (monomeric actin) exists in equilibrium with F-actin (filamentous actin) in living cells. The balance is regulated by multiple actin-binding proteins.
-
TB-500 has been reported to bind monomeric G-actin through the actin-binding sequence derived from Thymosin Beta 4 through the actin-binding sequence inherited from the parent Thymosin Beta 4 protein.
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Bound G-actin is sequestered from the polymerisation pathway. It cannot be incorporated into growing F-actin filaments while TB-500 is bound.
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The cellular G-actin pool effectively expands, while the F-actin pool is reduced. The balance shift influences downstream cytoskeletal dynamics.
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In published in-vitro research models, this actin sequestration mechanism is studied in cellular migration assays, cell shape research, and cytoskeletal remodelling research.
Documented Research Pathways for TB-500
In published in-vitro research literature, TB-500 has been investigated across several distinct pathways, including G-actin binding kinetic studies, cellular migration research in fibroblast and endothelial cell line models, cytoskeletal remodelling research, angiogenesis research in endothelial cell models, and combined research protocols paired with BPC-157 (which acts through a mechanistically separate pentadecapeptide signalling pathway). Combined TB-500 and BPC-157 research protocols appear frequently in published in-vitro peptide literature.
TB-500 vs BPC-157: Mechanistically Distinct Recovery Research Compounds
TB-500 and BPC-157 are the two most extensively studied recovery research peptides published in in-vitro literature, and they are frequently combined in multi-compound research protocols. The scientific rationale for combining them is mechanistic independence. TB-500 acts through actin sequestration (binding monomeric G-actin to influence cytoskeletal dynamics). BPC-157 has been investigated in published research for effects on cellular signalling pathways, angiogenic factor expression, and fibroblast-related processes). The two pathways are completely separate, which makes each compound function as an independent variable within the same research protocol. This is the analytical foundation of the combined research design.
|
Property |
TB-500 |
BPC-157 |
|---|---|---|
|
Sequence length |
17 amino acid fragment |
15 amino acid pentadecapeptide |
|
Source |
Fragment of Thymosin Beta 4 protein |
Fragment of human gastric protective protein |
|
Molecular weight |
≈ 4963.44 Da |
≈ 1419.55 Da |
|
Primary mechanism |
G-actin sequestration |
Pentadecapeptide signalling pathways |
|
Key research areas |
Cell migration, cytoskeletal dynamics, angiogenesis |
Angiogenesis, fibroblast biology, growth hormone receptor interactions |
|
Mechanistic independence |
Yes, no overlap with the BPC-157 pathway |
Yes, no overlap with TB-500 pathway |
For UK research programmes running the TB-500 plus BPC-157 combined protocol, the Regenesis Complex bundle from Ascend Peptides UK pairs both compounds at £55 with a single supplier batch matching. For the complete mechanistic comparison and the analytical rationale behind combined recovery research protocols, see the TB-500 vs BPC-157 research peptide comparison guide on the Ascend Peptides UK research blog. For the parallel BPC-157 educational content, see the ” What is BPC-157 guide.
TB-500 Research Applications in UK Laboratory Research
UK laboratory researchers working with TB-500 typically apply the compound across four research application areas. The application chosen depends on the specific experimental focus of the research programme. Each application has a substantial published in-vitro literature base.
Application 1: G-actin Binding Kinetics Research
The most fundamental TB-500 research application is the study of G-actin binding kinetics at the protein-protein interaction level. Research applications include binding affinity measurements (typically performed in vitro using purified G-actin and TB-500), structural studies of the TB-500 to G-actin complex, and comparative binding studies against the parent Thymosin Beta 4 protein to confirm that the 17 amino acid fragment retains the actin-binding activity of the full-length 43 amino acid protein.
Application 2: Cellular Migration Research in In-Vitro Models
Cellular migration depends on the dynamic regulation of the actin cytoskeleton. TB-500 has been studied in cell migration assays using fibroblast and endothelial cell line models, examining how G-actin sequestration affects migration kinetics, directionality, and persistence. The research application is relevant to broader in-vitro tissue research models and to in-vitro regenerative biology research at the cellular level.
Application 3: Cytoskeletal Remodelling Research
Beyond cell migration, the actin cytoskeleton regulates cell shape, cell division, and intracellular trafficking. TB-500 has been used as a research tool to study cytoskeletal remodelling in various cellular research models, particularly where the experimental design requires shifting the G-actin to F-actin equilibrium as an independent variable. This research application sits at the intersection of cellular biology and cytoskeletal biophysics.
Application 4: Combined TB-500 plus BPC-157 Multi Compound Research
The most extensively published TB-500 research application is the combined protocol with BPC-157. The combined actin sequestration plus pentadecapeptide signalling activation in cellular research models produces additive effects through mechanistically independent pathways. This research application accounts for a substantial proportion of published TB-500 literature and is the principal reason TB-500 appears alongside BPC-157 in the Ascend Peptides UK bundle range. For combined three-compound recovery research designs, GHK-Cu adds a third independent pathway (copper-dependent cellular research), with all three compounds available in the Tri-Regenerative Complex bundle.
Before Ordering TB-500: Free Research Buyer Starter Pack
The Research Buyer Starter Pack is a free downloadable guide for UK research buyers evaluating peptide suppliers. It converts the documentation framework into a practical buyer checklist covering exactly what to verify before ordering TB-500 or any other research peptide. Run any supplier against the checklist, including Ascend Peptides UK, to confirm the documentation standard before purchase.
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Research Buyer Starter Pack
A practical guide for UK research buyers. What to check before ordering TB-500 or any research peptide. What documentation to request from any supplier? What storage and dispatch standards to expect.
Inside the checklist:
✓ Product name verification — confirm test was performed on the correct compound
✓ Batch / lot number check — must name the specific vial lot
✓ Date of testing — must be recent and apply to current stock
✓ HPLC purity result — must state ≥98% and the analytical method
✓ LC-MS molecular identity — must confirm molecular weight match
✓ Laboratory issuing CoA — must be an independent third-party testing lab
✓ Method transparency — analytical method documented and reproducible
✓ CoA authentication — reference, signature, or verifiable identifier
✓ Pre-purchase availability — CoA must be accessible BEFORE the order is placed
For research professionals only — instant download, no payment required
TB-500 UK Supplier Standards: What to Verify Before Purchase
TB-500 is among the most heavily counterfeited research peptides in the UK research peptide market due to its commercial demand and the technical difficulty of correctly synthesising the 17-amino acid fragment. One reported quality concern in the research peptide market is substitution with incomplete or lower-molecular-weight peptide fragments. These shorter fragments may appear similar in lyophilised form but have substantially lower molecular weights detectable by LC-MS analysis. Four documentation standards distinguish a verified UK supplier of TB-500 from an unverified one. The complete framework is set out on the batch verification page.
|
Documentation Standard |
Industry Norm |
Ascend Peptides UK |
|---|---|---|
|
HPLC purity verification |
Self-reported by the supplier |
Independent HPLC by Janoshik, ≥98% verified |
|
LC-MS molecular identity |
Often not performed |
LC-MS confirmation on every batch (verifies 4963.44 Da intact fragment) |
|
Batch-specific Certificate of Analysis |
Generic or unavailable |
Per batch CoA tied to vial lot number |
|
UK dispatch standards |
3 to 7 working days |
Same day UK dispatch before 16:00 GMT |
Every TB-500 batch supplied by Ascend Peptides UK is independently HPLC verified at ≥98% purity and LC-MS confirmed for molecular identity, with the measured molecular weight (≈ 4963.44 Da) confirming the intact 17 amino acid fragment. The Janoshik Certificate of Analysis is publicly accessible from the CoA archive before the order is placed. For the complete research grade standards framework that defines what “research grade” means in the UK laboratory peptide supply, see the research grade standards page.
TB-500 Storage and Reconstitution Protocol
TB-500 follows the standard storage protocol applied across the Ascend Peptides UK research peptide catalogue. Lyophilised TB-500 powder is supplied in a sealed glass vial and should be stored at −20°C until reconstitution. Following reconstitution with BP-grade bacteriostatic water (water for injection with 0.9% benzyl alcohol preservative), the reconstituted solution should be stored at 2 to 8°C and used within the research literature-recommended in-use period (typically 28 days at refrigerated storage). The complete storage protocol is set out in the peptide storage guide.
Key Storage Standards for TB-500
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Lyophilised TB-500 storage: −20°C in the original sealed vial until reconstitution.
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Reconstitution medium: BP-grade bacteriostatic water (0.9% benzyl alcohol) for standard research protocols.
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Reconstituted TB-500 storage: 2 to 8°C in the original vial with reconstitution date labelled.
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In use period: typically 28 days at 2 to 8°C following reconstitution.
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Avoid freezing reconstituted solutions where possible. Freeze-thaw cycles can drive aggregation, which is particularly relevant for larger peptides like TB-500.
TB-500 in Combined Research Bundles
TB-500 appears in three Ascend Peptides UK research bundles, each designed for a specific multi-compound research protocol. The bundle pricing offers single supplier batch matching (where all compounds in the research design come from the same verified supplier and are tested against the same documentation standard) at a reduced unit cost.
|
Bundle |
Compounds Included |
Price |
Research Application |
|---|---|---|---|
|
Regenesis Complex |
BPC-157 10mg + TB-500 10mg |
£55 |
Commonly referenced dual-compound in-vitro research combination |
|
Tri-Regenerative Complex |
BPC-157 10mg + TB-500 10mg + GHK-Cu 100mg |
£85 |
Three compound recovery research programmes covering pentadecapeptide signalling, actin sequestration, and copper-dependent pathways |
|
Full Stack |
BPC-157 10mg + TB-500 10mg + CJC-1295 (Without DAC) 10mg + Ipamorelin 10mg |
£100 |
Comprehensive four-compound multi-pathway research design covering cytoskeletal and GH-axis related research pathways |
The Regenesis Complex pairs TB-500 with BPC-157 for the most studied combined recovery research protocol. The Tri-Regenerative Complex adds GHK-Cu for three compound research designs covering three mechanistically independent pathways. The Full Stack bundles TB-500 and BPC-157 with the GH axis compounds CJC-1295 and Ipamorelin for comprehensive multi-pathway research programmes. For the parallel GHK-Cu educational content, see the ” What is GHK-Cu guide.
Why UK Researchers Source TB-500 from Ascend Peptides UK
- ≥98% HPLC purity verified independently by Janoshik laboratory on every batch.
- LC-MS molecular identity confirmation on every batch, critical for distinguishing the intact 17 amino acid fragment from shorter substituted Thymosin Beta 4 fragments.
- Publicly verifiable Certificate of Analysis tied to the specific vial lot number.
- Same day UK dispatch before 16:00 GMT via Royal Mail Tracked 24.
- FREE 10ml BP grade bacteriostatic water on orders over £75.
- Bundle options available: Regenesis Complex (BPC+TB) £55, Tri-Regenerative Complex (adds GHK-Cu) £85, Full Stack £100.
- Complete recovery research peptide range stocked together for single supplier batch matching across BPC-157, TB-500, and GHK-Cu.
- Scientific content reviewed by an MBBS-qualified medical reviewer.
What Is TB-500? Frequently Asked Questions
What does TB-500 stand for?
TB-500 is the developmental research code name for a synthetic peptide fragment derived from Thymosin Beta 4 (TB4). The number 500 is a code identifier, not a structural property. The compound itself is a 17-amino acid fragment containing the actin-binding domain of the parent TB4 protein.
Is TB-500 the same as Thymosin Beta 4?
No. Thymosin Beta 4 (TB4) is the full 43 amino acid native intracellular protein. TB-500 is a synthetic 17-amino acid fragment of TB4 that contains the actin-binding domain of the parent protein. The fragment is designed to retain actin-binding properties associated with the full-length protein but in a smaller and more analytically tractable peptide format. The two compounds are structurally different even though they share the actin-binding mechanism.
What is the molecular structure of TB-500?
TB-500 is a 17-amino acid peptide fragment with the molecular formula C212H350N56O78S and molecular weight approximately 4963.44 Da. The sequence corresponds to the actin-binding domain of Thymosin Beta 4. The full molecular identity is confirmed on every Ascend Peptides UK batch by LC-MS analysis through Janoshik laboratory.
What is TB-500 used for in research?
In published in-vitro research literature, TB-500 has been studied across four principal application areas: G-actin binding kinetic research, cellular migration research in fibroblast and endothelial cell line models, cytoskeletal remodelling research, and combined multi-compound research protocols paired with BPC-157. All research applications are conducted in in-vitro cellular research models, not in human or veterinary clinical applications.
How does TB-500 differ from BPC-157?
TB-500 and BPC-157 are mechanistically distinct compounds. TB-500 is a 17-amino acid Thymosin Beta 4 fragment acting through G-actin sequestration. BPC-157 is a 15-amino acid pentadecapeptide acting through pentadecapeptide signalling pathways (including angiogenic factor expression and fibroblast biology). Mechanistic independence is the analytical foundation for combining the two compounds in multi-compound research protocols. See the TB-500 vs BPC-157 comparison guide for the complete mechanistic comparison.
Why are TB-500 and BPC-157 combined in research protocols?
The two compounds act through mechanistically independent pathways. TB-500 sequesters G-actin to influence cytoskeletal dynamics. BPC-157 acts through pentadecapeptide signalling on angiogenesis, fibroblast biology, and growth hormone receptor pathways. The distinct proposed mechanisms allow the compounds to be evaluated separately within the same experimental design. within the same research protocol. Combined use has been explored in published in-vitro research models because the compounds act through mechanistically distinct pathways. The Regenesis Complex bundle from Ascend Peptides UK pairs both compounds at £55.
What is the WADA status of TB-500?
TB-500 is listed on the World Anti-Doping Agency (WADA) Prohibited List under category S2 (Peptide Hormones, Growth Factors, Related Substances and Mimetics). It is prohibited at all times for athletes subject to WADA jurisdiction. TB-500 supplied by Ascend Peptides UK is for in-vitro laboratory research only and is not represented as a substance for use by athletes or in any human or veterinary application.
What is the MHRA status of TB-500 in the UK?
TB-500 is not licensed as a medicinal product under the UK Human Medicines Regulations 2012. It is supplied strictly for in vitro laboratory research. The Medicines and Healthcare products Regulatory Agency (MHRA) is the relevant medicines regulator in the UK post Brexit (replacing the previous European Medicines Agency route).
How much does TB-500 cost from Ascend Peptides UK?
TB-500 is supplied at £35 per vial from Ascend Peptides UK. Bundle options reduce the unit cost: the Regenesis Complex bundles TB-500 with BPC-157 for £55, and the Tri-Regenerative Complex adds GHK-Cu for £85. All orders over £75 qualify for a free 10ml BP grade bacteriostatic water.
Order TB-500 from Ascend Peptides UK with Same Day Dispatch
Browse the TB-500 product page for batch-specific Certificate of Analysis documentation and same-day UK dispatch. For combined recovery research protocols, the Regenesis Complex bundle (TB-500 plus BPC-157, £55) offers single supplier batch matching at the reduced bundle price. For the three-compound recovery research, the Tri-Regenerative Complex bundle (TB-500 plus BPC-157 plus GHK-Cu, £85) adds the third independent pathway. For the complete recovery research category framework, see the recovery research peptides UK page, or start with the main research peptides UK hub for the complete supplier model.
RESEARCH USE ONLY
All products supplied by Ascend Peptides UK are intended strictly for in vitro laboratory research purposes only. TB-500 is not a licensed medicinal product under the UK Human Medicines Regulations 2012 and is not for human or veterinary use. No dosing or administration guidelines are provided. Products are supplied to qualified research professionals only.
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