Made in USA · ≥99% HPLC
Research Peptide
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TB-500 (Thymosin Beta-4) 10mg
Thymosin Beta-4Tβ4Timbetasin (INN)
A 43-amino-acid acetylated synthetic Thymosin Beta-4, supplied lyophilized for in vitro actin-binding and cell-migration research.
$59.95
20 in stock
For laboratory and research use only. Not for human consumption.
This product is not a drug, food or cosmetic. It is sold exclusively to qualified researchers and licensed laboratories.
20 in stock
Tested by Freedom Diagnostics TestingHPLC purity + LC-MS identityLot-matched COA on-site
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Verified COA
Batch-tested & posted · Freedom Diagnostics
Purity (HPLC-UV)99.127%
Identity (LC-MS)Confirmed
Net content9.97 mg
ReportedDec 30, 2025
US-synthesizedMade & lab-released in the United States
Independent COAThird-party Certificate of Analysis per lot
HPLC + LC-MSPurity by HPLC, identity by mass spectrometry
Same-day dispatchOrders before 2 PM CT ship the same business day
What is TB-500?
TB-500 is a synthetic 43-amino-acid acetylated peptide corresponding to thymosin β-4 (Tβ4), a naturally occurring actin-sequestering protein. It binds monomeric G-actin through the central LKKTETQ motif, regulating the cytoplasmic actin pool available for filament elongation, and is studied for its role in cell migration and angiogenesis signaling. Its low molecular weight, absence of disulfide bonds, and lack of extracellular-matrix binding let it cross tissue compartments readily in research models.
Research areas where laboratories buy TB-500 for in vitro work include actin pharmacology separating Tβ4 effects from those of its Ac-SDKP cleavage fragment, migration and scratch assays in dermal fibroblasts, keratinocytes and corneal epithelial cells, angiogenesis readouts in HUVEC tube-formation and aortic-ring models, cardiac and skeletal-muscle models in rodents, and cytoskeletal imaging with fluorescent G-actin and F-actin reporters. TB-500 / thymosin β-4 is not approved by the FDA for any indication.
Every lot, independently verified
Independently third-party tested and matched to the lot ID printed on your vial. Values below are from the latest released lot.
99.13%
HPLC-UV Purity
Passed full QC panel
Independent third-party lab (Freedom Diagnostics Testing)
View COA
Latest batch · tested 30 Dec 2025 · Freedom Diagnostics (USA)
Lot details
ProductTB-500 10 mg
COA ref #2512290134
AppearanceWhite lyophilized powder
Received29 Dec 2025
Reported30 Dec 2025
Full QC panel · third-party lab7 assays
Purity (HPLC-UV)99.127% ✓
Identity (LC-MS)Thymosin Beta-4 ✓
HPLC conformity (2×)Confirmed ✓
Net content (10 mg label)9.97 mg ✓
Heavy metals (ICP-MS)Not Detected ✓
SterilityNo Growth ✓
Endotoxin (USP <85>)Within limits ✓
Every lot is released against Koi's full QC panel — HPLC purity, LC-MS identity, net peptide content, heavy metals, sterility, and endotoxin — by an independent third-party laboratory (Freedom Diagnostics Testing). Values shown are from the latest released lot (accession 2512290134, reported 30 Dec 2025) and vary batch to batch; the lot-specific certificate is published in our public COA library and matched to the lot ID printed on the vial.
Browse full COA library →
Compound information
Chemical & structural reference data — specifications, molecular profile and handling.
Product Specifications
CompoundTB-500 (synthetic thymosin β-4; 43-aa acetylated peptide)
Vial size10 mg
Purity≥99% by HPLC
Identity confirmationMass spectrometry
FormLyophilized white powder
Appearance in solutionClear, colorless solution
ManufacturingSynthesized and lyophilized in the United States
Quality testingIndependent third-party laboratory release (Freedom Diagnostics Testing)
Molecular Profile
Type43-aa acetylated β-thymosin
SequenceAc-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES
Molecular formulaC212H350N56O78S
Molecular weight4963.44 g/mol
CAS number77591-33-4
PubChem CID16132341
StructureSingle Met (pos 6); no disulfides
Storage & Handling
AppearanceLyophilized white powder
SolubilityFreely water-soluble
Storage · powder−20 °C, desiccated, dark (−80 °C long-term)
In solution2–8 °C; aliquot & freeze, avoid freeze-thaw
TB-500 Mechanism of Action
- Binds monomeric G-actin through the central LKKTETQ motif, sequestering actin monomers and modulating the cytoplasmic pool available for filament elongation.
- Promotes endothelial migration, tube formation, and vessel-network density in HUVEC tube-formation and aortic-ring angiogenesis models.
- Engages the N-terminal Ac-SDKP cleavage pathway, where prolyl oligopeptidase liberates the tetrapeptide that carries its own hematopoiesis and fibrosis activity.
- Crosses tissue compartments readily — low molecular weight, no disulfide bonds, no extracellular-matrix binding.
- Studied for epicardial progenitor activation and fibrosis-marker expression in rodent cardiac ischemia-reperfusion models.
TB-500 Research Applications
- Actin pharmacology — separating Tβ4 effects dependent on the LKKTETQ motif from those of the Ac-SDKP tetrapeptide.
- Migration and scratch assays in dermal fibroblasts, keratinocytes, and corneal epithelial cells.
- Angiogenesis readouts in HUVEC tube-formation and aortic-ring models.
- Cardiac and skeletal-muscle models in rodents, including ischemia-reperfusion designs.
- Cytoskeletal imaging with fluorescent G-actin and F-actin reporters tracking the polymerization equilibrium.
Why Buy TB-500 from Koi Peptides?
- Every batch of Koi TB-500 is synthesized and lyophilized in the United States, then released against independent third-party laboratory (Freedom Diagnostics Testing) testing.
- Each lot is tested by HPLC for purity, LC-MS for identity confirmation, and screened for endotoxin before release.
- The lot ID is printed on every vial and ties back to a public COA library, so researchers can verify documentation before they buy and after the vial arrives.
- Orders placed before 2 PM CT ship the same business day, and shipping is free on orders over $200.
References
The laboratory and preclinical research behind TB-500 — cited for scientific context.
FASEB Journal
Thymosin β4 stimulates directional migration of human umbilical vein endothelial cells
J. Biological Chemistry
Thymosin β4 and Fx, an actin-sequestering peptide, are indistinguishable
Ann. NY Acad. Sci.
Thymosin β4: structure, function, and biological properties
View all references +
- Safer, D., et al. (1991). Thymosin β4 and Fx, an actin-sequestering peptide, are indistinguishable. Journal of Biological Chemistry, 266(7), 4029–4032.
- Crockford, D., et al. (2010). Thymosin β4: structure, function, and biological properties. Annals of the New York Academy of Sciences, 1194, 179–189. doi.org/10.1111/j.1749-6632.2010.05492.x
- Malinda, K. M., et al. (1997). Thymosin β4 stimulates directional migration of human umbilical vein endothelial cells. FASEB Journal, 11(6), 474–481. doi.org/10.1096/fasebj.11.6.9194528
- Smart, N., et al. (2007). Thymosin β4 induces adult epicardial progenitor mobilization and neovascularization. Nature, 445(7124), 177–182. doi.org/10.1038/nature05383
- Xue, B., & Robinson, R. C. (2013). Guardians of the actin monomer. European Journal of Cell Biology, 92(10–11), 316–332. doi.org/10.1016/j.ejcb.2013.10.012
- Cavasin, M. A., et al. (2004). Prolyl oligopeptidase is involved in release of the antifibrotic peptide Ac-SDKP. Hypertension, 43(5), 1140–1145. doi.org/10.1161/01.HYP.0000126172.01673.84
- Liu, J. M., et al. (2003). Ac-SDKP is generated from thymosin β4 in vivo by ACE N domain. Journal of Biological Chemistry, 278(40), 38513–38520. doi.org/10.1074/jbc.M209853200
- Sosne, G., et al. (2010). Biological activities of thymosin β4 defined by active sites in short peptide sequences. FASEB Journal, 24(7), 2144–2151. doi.org/10.1096/fj.09-142307
Regulatory Status
Regulatory status — provided for research context.
Regulatory Status
Regulatory status — provided for research context.
Research Use
This research-grade material is supplied by Koi Peptides for laboratory research only. It is not approved by the FDA for any indication, and is not formulated, packaged or labeled as a drug, food or cosmetic.
Disclaimer
For laboratory and research use only. Not for human consumption. This product is not a drug, food or cosmetic. It is sold exclusively to qualified researchers and licensed laboratories. These statements have not been evaluated by the Food and Drug Administration. This product is not intended to diagnose, treat, cure or prevent any disease.
Frequently Asked Questions About TB-500
What is TB-500 used for in research?+
TB-500 serves as the reference thymosin β-4 compound in actin pharmacology and cell-migration research. In vitro work covers migration and scratch assays in dermal fibroblasts, keratinocytes, and corneal epithelial cells; HUVEC tube-formation and aortic-ring angiogenesis readouts; and cytoskeletal imaging with fluorescent G-actin/F-actin reporters. Rodent studies use it in cardiac and skeletal-muscle models.
What purity is Koi's TB-500?+
≥99% pure by HPLC-UV — the latest released lot tested 99.127%, with identity confirmed by LC-MS as thymosin β-4 and a measured net peptide content of 9.97 mg in a 10 mg vial. Every lot is released against an third-party full QC panel — HPLC purity, LC-MS identity, net peptide content, heavy metals, sterility, and endotoxin (USP <85>) — and the COA is published against the lot number printed on the vial.
How do I prepare a solution of TB-500?+
Dissolve in sterile water at neutral pH — TB-500 is freely water-soluble and requires no acidic buffer. Add diluent slowly down the vial wall rather than directly onto the cake to limit foaming, and avoid vortexing. For sterile cell-culture work, filter through a 0.22 µm low-protein-binding filter before adding to cultures.
What is the CAS number for TB-500?+
The CAS number for TB-500 (thymosin β-4) is 77591-33-4 and the PubChem CID is 16132341. The molecule is also cataloged as thymosin β-4, Tβ4, and timbetasin (INN), with a molecular weight of 4963.44 g/mol.
Is TB-500 for human use?+
No. This product is for laboratory and research use only and is not for human consumption. It is sold exclusively to qualified researchers and licensed laboratories.
Does TB-500 come with a Certificate of Analysis?+
Yes. The lot-specific Certificate of Analysis is published in our public COA library and matched to the lot ID printed on the vial. It covers HPLC purity, LC-MS identity, net peptide content, heavy metals, sterility, and endotoxin (USP <85>), so researchers can verify documentation before they buy and after the vial arrives.
How should TB-500 be stored?+
Hold the lyophilized vial at −20 °C, sealed and protected from light and moisture; −80 °C is preferred for long-term storage. Once dissolved, store at 2 to 8 °C for short-term use, or aliquot and freeze for longer storage. The single methionine at position 6 is oxidation-sensitive once dissolved, so minimize air exposure and avoid repeated freeze-thaw cycles.
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