TB-500 (Thymosin Beta-4) · Research brief

Buy TB-500 (Thymosin Beta-4): Vial Sizes, Pricing & COAs

Real Peptides Research TeamEditorial

Updated September 8, 20269 min read

40 WORDS

Short answer

Key takeaways

Thymosin beta-4 is a 43-amino-acid peptide of roughly 4.9 kDa, while much of the material marketed as TB-500 is a short acetylated fragment built around the LKKTET actin-binding motif.
Labeled vial mass is gross lyophilised weight; net peptide content after trifluoroacetate counterions and residual water is always lower and must be read from the certificate of analysis.
A TB-500 thymosin beta-4 10mg vial only saves money when its price ratio against the 5mg vial is below 2:1.
A certificate of analysis without a lot number matching the physical vial certifies nothing about the material in your hands.
Researchers who buy TB-500 (thymosin beta-4) should compare cost per milligram of documented peptide content, not cost per labeled milligram.
HPLC purity and peptide content are different measurements, and suppliers who publish only the first are answering the easier question.

The number printed on a peptide vial and the number on its certificate of analysis are frequently not the same number. Labeled mass is gross lyophilised weight. Net peptide content, once trifluoroacetate counterions and residual moisture are subtracted, sits lower. Anyone about to buy TB-500 (thymosin beta-4) for laboratory work is really purchasing two things at once: a mass of white powder, and a set of analytical documents that states what that powder actually is.

Our team fields this from research buyers constantly, and the pattern repeats. People compare vial prices across three tabs, then never request the batch data that would make the comparison mean anything.

Where can researchers buy TB-500 (thymosin beta-4), and what should a vial cost?

Researchers who buy TB-500 (thymosin beta-4) receive a lyophilised, research-use-only powder, most commonly supplied in 5mg and 10mg presentations. Price scales with labeled mass, but the only comparison worth running is cost per milligram of verified peptide content, confirmed on a batch-specific certificate of analysis showing RP-HPLC purity and mass spectrometry identity. Request that document before ordering.

Here is the part most product listings quietly skip. A large share of material sold under the TB-500 name is not the full 43-amino-acid thymosin beta-4 protein. It is a short synthetic fragment built around the actin-binding motif, which changes the molar quantity delivered per milligram by roughly an order of magnitude. This article covers what those two molecules are, how to run the price-per-milligram math on 5mg and 10mg vials, and how to read a certificate of analysis line by line.

Full-length thymosin beta-4 and the LKKTET fragment are not the same purchase

Thymosin beta-4 (Tβ4) is a naturally occurring 43-amino-acid peptide of roughly 4.9 kDa, described in the literature as the principal G-actin sequestering molecule in mammalian cells. It binds monomeric actin through a conserved motif, LKKTET, and holds it in a non-polymerising pool. Research also describes Ac-SDKP, a tetrapeptide liberated from the N-terminal region of Tβ4 by prolyl oligopeptidase, which the antifibrotic literature has examined separately.

The compound circulating commercially as TB-500 is frequently the acetylated seven-residue fragment spanning that LKKTET motif, not the intact 43-mer. Labs that buy TB-500 (thymosin beta-4) expecting full-length protein and receive a short fragment have not necessarily received an impure product. They have received a different molecule with a different molecular weight, and that matters enormously: one milligram of a roughly 900 Da fragment contains far more molecules than one milligram of a 4.9 kDa protein. Equal-mass comparisons across suppliers are not equal-molar comparisons, and any study design built on mass alone will produce results that cannot be replicated elsewhere.

So the first question is never price. It is sequence. A supplier should be able to state the exact amino acid sequence and the theoretical molecular weight of what ships, and the mass spectrometry trace on the certificate of analysis should confirm it. Everything in this article is educational information about laboratory materials; these compounds are not FDA-approved drugs and are not supplied for human or veterinary consumption.

How to compare TB-500 pricing across 5mg and 10mg vials

Run the arithmetic in this order: labeled mass, then peptide content percentage, then chromatographic purity, then shipping. A TB-500 thymosin beta-4 5mg vial and a TB-500 thymosin beta-4 10mg vial priced at a flat 2:1 ratio offer no per-milligram saving at all. The only genuine economy in the larger presentation is amortised shipping and one fewer cold-chain handoff.

Peptide content is where most buyers lose money without noticing. Synthesised peptides purified by reverse-phase HPLC carry residual trifluoroacetate counterions and adsorbed water, so gross lyophilised mass overstates net peptide. For illustration only: a vial labeled 5mg with a peptide content of 80% by amino acid analysis delivers roughly 4mg of actual peptide. A competitor charging 15% more per vial with peptide content documented at 95% is the cheaper source. That single line item on the COA reorders the entire market, and it is the reason a headline TB-500 price tells you almost nothing.

The honest way to buy TB-500 (thymosin beta-4) at a fair rate is to divide the vial price by documented net peptide mass, not by labeled mass, and compare that figure across suppliers. Anyone shopping TB-500 thymosin beta-4 for sale across multiple vendors should also check minimum order thresholds and whether pooled multi-compound orders reduce per-shipment cost. Researchers running parallel recovery-focused work often source several compounds at once from our full peptide catalog, which consolidates freight rather than paying it three times.

Reading a certificate of analysis line by line

A certificate of analysis is a batch document, not a marketing asset. Every decision to buy TB-500 (thymosin beta-4) should hinge on whether the COA is specific to the lot number physically printed on the vial you receive. If the lot on the paper and the lot on the label disagree, the document certifies nothing about your material.

A complete COA for a synthetic peptide carries, at minimum: an RP-HPLC chromatogram with retention time and area percentage rather than a bare purity number; mass spectrometry data (ESI-MS or MALDI-TOF) showing observed mass against theoretical mass; peptide content determined by amino acid analysis or nitrogen determination; water content by Karl Fischer titration; residual TFA; appearance; the sequence in one-letter or three-letter code; manufacture date; and an analyst or QC signature.

The red flags are consistent. A purity figure with no attached chromatogram is an assertion, not data. An undated COA, or one with the lot field left blank, is a template. A document identical across every product page on a site was never generated by an instrument. And a COA showing HPLC purity but omitting peptide content is telling you how clean the peptide is while staying silent on how much peptide is in the jar.

We have reviewed a great many of these across suppliers, and the omission is almost always peptide content. That is not an accident. It is the one number that lets a buyer calculate true cost per milligram, which is exactly why we publish batch-specific documentation alongside every compound, including research bundles like the Healing Total Recovery Bundle.

Buy TB-500 (Thymosin Beta-4): 5mg vs 10mg Vial Comparison

The table below compares the two standard presentations plus multi-vial ordering, focused on what each format changes about cost, documentation and laboratory handling. Use it to decide format before you compare prices.

Presentation	What the labeled mass covers	How cost per milligram behaves	COA and handling notes	Bottom line
5mg vial	Gross lyophilised weight including counterions and residual water, so net peptide sits below 5mg	Usually the highest per-milligram figure; suits pilot or method-development work	One lot document per vial; less material lost if a single vial is compromised in transit	Best for first orders and for validating a supplier's documentation before committing budget
10mg vial	Same gross-weight convention at double the labeled mass; peptide content percentage applies identically	Frequently lower per milligram, but only if the price ratio is under 2:1 against the 5mg presentation	Fewer vials to track, though one temperature excursion now affects twice the material	Sensible once a lot has been verified and the research protocol has a defined, ongoing material requirement
Multi-vial or bundled order	Aggregate labeled mass across several vials, often spanning more than one lot number	Lowest effective cost once freight and cold-pack charges are spread across the shipment	Requires a separate COA per lot; never accept one document covering mixed lots	Strongest value for established laboratories, provided lot-level documentation is checked individually

What If: TB-500 Sourcing and Handling Scenarios

What if the powder in the vial looks like almost nothing?

Weigh nothing and assume nothing; check the COA instead. Lyophilised peptide cake volume depends on fill volume, excipient content and freeze-drying parameters, so 5mg can present as a barely visible film on the glass or as a fluffy plug filling a third of the vial. Neither appearance indicates mass. Some cakes also collapse into a thin ring during shipping vibration, which is cosmetic rather than a stability failure.

What if the lot number on the COA doesn't match my vial?

Stop and contact the supplier before opening anything. A mismatched lot means the analytical data you were given describes a different synthesis batch, with different purity, different peptide content and potentially different impurity profile. Reputable suppliers will issue the correct lot document within a day or replace the material. If a vendor tells you lot numbers are interchangeable, that is a sourcing decision made for you.

What if the shipment sat at ambient temperature for several days?

Record the transit conditions, then ask the supplier for the batch stability data. Lyophilised peptides are considerably more tolerant of short ambient excursions than reconstituted solutions, which is precisely why they ship dry. Standard laboratory practice stores lyophilised material at −20°C or colder long term, with reconstituted solution refrigerated at 2–8°C. Documented deviation matters more than assumption here, because degradation is invisible in a dry powder.

What if the research context is veterinary rather than in vitro?

Treat the regulatory boundary as absolute: research-use-only compounds are not veterinary medicines and are not supplied for administration to animals. Any question involving a living animal belongs with a licensed veterinarian, who can advise on approved products and legal prescribing routes. Suppliers of research chemicals cannot and should not fill that role, regardless of what the literature reports about a given peptide.

The uncomfortable truth about 99% purity claims

Let's be direct about this: a stated purity of 99% with no chromatogram attached is a number typed into a template. RP-HPLC purity measures the proportion of UV-absorbing material eluting as the main peak. It says nothing about how much peptide is in the vial, nothing about counterion load, and nothing about whether the sequence is the one you ordered. A supplier can honestly print 99% purity on a vial whose contents are 70% peptide by mass. Both figures are true. Only one of them is on most websites, and it is never the inconvenient one.

Every decision to buy TB-500 (thymosin beta-4) eventually reduces to a question of documentation rather than chemistry, because two vials of identical white powder are indistinguishable to the eye, the nose and the balance. The chromatogram is the product. The mass spectrum is the product. The powder is just the delivery format. Labs that internalise that stop shopping on headline price within about one order cycle, and they stop discovering six months into a study that their week-one material and their week-twenty material were never the same molecule.

References

Peer-reviewed sources on TB-500 (Thymosin Beta-4) indexed in PubMed, listed for research context. Real Peptides supplies TB-500 (Thymosin Beta-4) for laboratory research use only.

Thymosin β4 alleviates sepsis-associated acute kidney injury by suppressing MAPK signaling pathway. Clinical science (London, England : 1979), 2026. PMID 42417058. doi:10.1042/CS20261084
Sprayable bioadhesive microcarriers loaded with Tβ4-Engineered ADSC exosomes for diabetic wound healing. Bioactive materials, 2026. PMID 42383202. doi:10.1016/j.bioactmat.2026.06.024
Thymosin beta 4 as an Alzheimer disease intervention target identified using human brain organoids. Stem cell reports, 2025. PMID 40816274. doi:10.1016/j.stemcr.2025.102601
Mechanistic study of the Tβ4/SLC7A11 signaling pathway regulating breast cancer evolution. Cellular signalling, 2025. PMID 40912522. doi:10.1016/j.cellsig.2025.112111
Thymosin β4 Regulates Tissue Inflammatory Response in Mouse Nonalcoholic Fatty Liver Disease by Promoting Macrophage M2-Type Polarization. Journal of inflammation research, 2025. PMID 40322536. doi:10.2147/JIR.S492814
Injectable Thymosin β4-Modified Hyaluronic Acid Hydrogel with Exosomes for Stem Cell Homing and Neuronic-Angiogenic-Osteogenic Coupled Cranial Repair. ACS nano, 2025. PMID 40528381. doi:10.1021/acsnano.4c10386
Secreted Expression of Thymosin β4 from Pinctada fucata in Pichia pastoris and Its Biological Activity. Biology, 2025. PMID 40427742. doi:10.3390/biology14050553
Thymosin β4 and the anti-fibrotic switch. International immunopharmacology, 2023. PMID 36580759. doi:10.1016/j.intimp.2022.109628

Questions

Thymosin beta-4 is a naturally occurring 43-amino-acid peptide of roughly 4.9 kDa that acts as the main G-actin sequestering molecule in mammalian cells. TB-500 is a market name frequently applied to a short synthetic fragment containing the LKKTET actin-binding motif rather than the intact 43-residue protein. Because their molecular weights differ substantially, one milligram of each contains very different molar quantities, so always confirm the exact sequence on the certificate of analysis.

Request the batch-specific certificate of analysis before ordering and confirm the lot number on the document matches the lot printed on the vial you receive. A usable COA includes an RP-HPLC chromatogram with area percentage, mass spectrometry confirming observed against theoretical mass, peptide content by amino acid analysis, and water content by Karl Fischer titration. A purity percentage with no supporting chromatogram is an assertion rather than data.

TB-500 price varies widely by supplier, vial size, purity specification and order volume, so published figures date quickly. The useful comparison is cost per milligram of documented net peptide content rather than cost per labeled milligram, because gross lyophilised weight includes counterions and residual moisture. Check current listed pricing directly against the peptide content figure on each supplier's certificate of analysis.

A TB-500 thymosin beta-4 5mg vial suits first orders and method development because it limits exposure while you validate a supplier's documentation. A TB-500 thymosin beta-4 10mg vial only delivers real savings when its price is less than double the 5mg presentation, since the primary economy is amortised shipping and cold-pack cost. Larger vials also concentrate risk: one handling failure affects twice the material.

TB-500 and thymosin beta-4 are supplied as research-use-only materials for laboratory and in vitro work. They are not FDA-approved drug products, are not sold for human or veterinary consumption, and are prohibited in competitive sport under World Anti-Doping Agency rules. Purchasers are responsible for compliance with the regulations that apply in their own jurisdiction and institution.

Standard practice is to keep lyophilised peptide powder at −20°C or colder for long-term storage, protected from light and moisture. Once reconstituted, solutions are typically refrigerated at 2–8°C and used within a short window, since peptides in solution degrade far faster than dry powder. Repeated freeze-thaw cycling is avoided by aliquoting, and any temperature deviation should be documented rather than estimated after the fact.

Lyophilised cake appearance depends on fill volume and freeze-drying parameters, not on mass. Five milligrams can present as a thin film on the vial wall or as a fluffy plug, and shipping vibration often collapses the cake into a ring at the base. Neither is evidence of short fill or degradation. The certificate of analysis and the fill records are the only reliable confirmation of mass.

Peptide content is the percentage of the vial's gross lyophilised weight that is actually peptide, with trifluoroacetate counterions and adsorbed water making up the remainder. It is measured by amino acid analysis or nitrogen determination and is a completely separate figure from HPLC purity. A batch can show 99% chromatographic purity while peptide content sits far lower, which is why suppliers who publish only purity are answering the easier question.

The two are studied through different mechanisms. Thymosin beta-4 is described primarily as a G-actin sequestering peptide involved in cell migration and cytoskeletal dynamics, while BPC-157 is a synthetic pentadecapeptide fragment studied in gastrointestinal and connective tissue models. Research on both remains largely preclinical, and neither is an approved therapeutic. Comparisons between them should be based on the specific model system under study rather than general recovery claims.

Yes, and consolidating an order is usually the largest single reduction in effective cost per milligram, because freight and cold-pack charges are spread across the shipment rather than repeated. The important caveat is documentation: multi-vial orders often span more than one synthesis lot, and each lot requires its own certificate of analysis. Never accept a single document presented as covering mixed lots.

The clearest signals are an undated certificate of analysis, a blank or mismatched lot field, an identical COA appearing across multiple different products, and a purity figure published without a chromatogram. Refusal to state the exact amino acid sequence is another. Suppliers who omit peptide content while advertising high purity are withholding the one number that would let you calculate true cost per milligram.

RESEARCH USE ONLY · NOT EVALUATED BY THE FDA