Guide
TB-500 reconstitution, storage and lab report guide
TB-500's numbers in one place: mass, its relationship to thymosin beta-4, vial size, concentration table and what its report should show.
Published September 4, 2026
TB-500 is the synthetic form of thymosin beta-4's active region, and at nearly 5,000 g/mol it is one of the heaviest peptides we sell.
| Peptide | Vial sizes | From |
|---|---|---|
| TB-500 (TB4) | 5mg, 10mg | $34.99 CAD |
| TB-500 Frag 17-23 | Single size | $59.99 CAD |
| BPC157 + TB500 Blend | 5mg + 5mg, 10mg + 10mg | $64.99 CAD |
Free shipping across Canada. Every vial ships with a QR code linking to its own batch lab report. See all peptides
Identity
| Formula | C212H350N56O78S |
| Molecular weight | 4963.44 g/mol |
| CAS | 77591-33-4 |
| Form | Acetylated thymosin beta-4 peptide |
| Vial size we sell | 5 mg |
The single sulfur in the formula is worth noting; it is one more thing an elemental or mass check can confirm.
Concentration, and why the molar number is small
| Vial | 1 mL | 2 mL | 3 mL | 5 mL |
|---|---|---|---|---|
| 5 mg | 5 mg/mL1.01 mM | 2.5 mg/mL0.504 mM | 1.67 mg/mL0.336 mM | 1 mg/mL0.201 mM |
| 10 mg | 10 mg/mL2.01 mM | 5 mg/mL1.01 mM | 3.33 mg/mL0.672 mM | 2 mg/mL0.403 mM |
TB-500 (TB4) vial sizes we sell, at four diluent volumes. Molarity uses 4963.44 g/mol. Other volumes
A 5 mg vial is about 1.007 micromoles. That is the lowest molar content per milligram of anything in the catalog apart from the recombinant proteins. If your protocol is written in molar units and you have been working with a small peptide, the numbers here will look unfamiliar. The TB-500 calculator has the weight preset.
Handling
Bacteriostatic water down the inside of the glass, swirl gently, never shake. Freezer for the dry powder long term, fridge short term; once reconstituted, fridge only, and aliquot rather than refreeze. The reconstitution guide is one page.
Reading its report
Observed mass near 4963.44, purity at 99% or higher by HPLC, matching batch number and a named lab. Scan the QR on the vial or look the batch up. Before you order, the Lab Reports tab on the product page sends you the latest batch's report by email.
The fragment and the blends
Residues 17 to 23 carry the actin-binding activity and we sell them separately. TB-500 vs TB-500 fragment 17-23 explains what you gain and lose by isolating them, and why a milligram of the fragment is seven times the molecules.
TB-500 also appears in three blends: with BPC-157, in GLOW and in KLOW. BPC-157 vs TB-500 covers why those two are paired so often.
Every TB-500 vial from pepuro ships free, from our Calgary, Toronto and Vancouver distribution centers, the same business day your e-Transfer clears, with a QR code on the vial that opens its independent, third-party lab report.
For research use only. Not for human or animal consumption.
Frequently asked questions
What is the molecular weight of TB-500?
+
4963.44 g/mol, formula C212H350N56O78S. It is one of the largest peptides in the catalog outside the recombinant proteins.
Is TB-500 the same as thymosin beta-4?
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TB-500 is the synthetic version of the active region of thymosin beta-4, supplied as the acetylated peptide. Thymosin beta-4 itself is a 43-residue natural peptide.
How much water do I add to a 5 mg TB-500 vial?
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1 mL gives 5 mg/mL, 2 mL gives 2.5 mg/mL, 5 mL gives 1 mg/mL. At 4,963 g/mol a 5 mg vial is only about 1 micromole.
What is the fragment version?
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Residues 17 to 23, the actin-binding stretch, sold separately at 729.83 g/mol. It is about a seventh the mass of the full peptide.
Related articles
- Where to buy a peptide blend in CanadaPeptide blends are sold in Canada as research chemicals. What a blend vial holds, how to reconstitute one, and how to check what is inside it.
- DSIP in Canada: what's sold and how to check itDSIP is sold in Canada as a research chemical for lab use. Vial sizes, prices, how the rules apply, and how to check that a vial is really DSIP.
- KLOW vs KPV: a four-peptide blend and a tripeptideKLOW contains KPV as one of its four peptides, so they are not alternatives. What separates an 80 mg blend vial from a 10 mg KPV vial, and how each is checked.
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