What this does
A 10 mg TB-500 vial in 2 mL of bacteriostatic water is 5 mg/mL. A 2 mg draw is 0.4 mL, or 40 units on a U-100 syringe. There is no published human dose for TB-500, and the name may refer to full-length thymosin beta-4 or only its active fragment.
The vial size above is the one Peptriva ships, read from the live listing. Change it if yours differs. The dose stays whatever you set — this tool does not suggest one.
What size vial does TB-500 come in?
The stocked vial is 10 mg, which is the market standard. Five-milligram vials also circulate.
The same vial at four water volumes:
| Water added | Concentration | Units for a 1 mg draw |
|---|---|---|
| 1 mL | 10 mg/mL | 10.0 units |
| 2 mL | 5 mg/mL | 20.0 units |
| 3 mL | 3.33333 mg/mL | 30.0 units |
| 5 mL | 2 mg/mL | 50.0 units |
Every row holds the same 10 mg. Water changes the concentration and the draw size, never the amount of peptide in the vial.
What dose has been studied?
None in humans, for the uses TB-500 is sold for. There is no published human dose to convert, which is why this page reports the arithmetic and stops there.
The molecular biology is genuinely good. Thymosin beta-4 makes up roughly 70–80% of all beta-thymosins in the body and binds monomeric G-actin at a 1:1 ratio, which is how a cell controls the machinery it uses to migrate into a wound. That is mechanism, not an outcome. The actin-binding mechanism covers it.
The TB-500 guide sets out the full evidence base, and BPC-157 vs TB-500 compares it with the compound it is most often paired with.
The trap on this one: which molecule is in the vial
This is the problem that makes TB-500 different from everything else in this catalog, and no calculator can solve it.
“TB-500” may mean full-length thymosin beta-4, or it may mean only the active fragment. They are different molecules with different masses, and suppliers do not consistently declare which one they made. A purity figure of 99% tells you the vial is pure; it does not tell you pure what.
So milligram-for-milligram equivalence between two vendors’ TB-500 is an assumption rather than a fact. The check is the mass spectrum on the certificate, not the purity line — see how to read a COA.
Practical consequence: the arithmetic above is exact, and what it is exact about depends on a document you have to open. The cardiac research covers where the full-length molecule’s evidence actually comes from.
Frequently asked questions
How many units is 2 mg of TB-500?
At 10 mg in 2 mL, which is 5 mg/mL, 2 mg is 0.4 mL — 40 units on a U-100 syringe. Change the water volume and that figure changes proportionally.
What is the correct TB-500 dose?
There is no published human dose for the uses TB-500 is sold for. The regenerative literature people quote is on full-length thymosin beta-4, which is not necessarily the molecule in the vial.
Are all TB-500 vials the same molecule?
No, and this is the compound's central problem. The name covers both full-length thymosin beta-4 and its active fragment. They have different masses and suppliers do not consistently say which they made. Check the mass spectrum, not the purity figure.
How much bacteriostatic water for a 10 mg TB-500 vial?
Your choice. 2 mL gives 5 mg/mL, 3 mL gives 3.33 mg/mL. The vial holds the same 10 mg either way; water only changes how large each draw is.
References
- American Society of Health-System Pharmacists (ASHP). Handbook on Injectable Drugs: Benzyl alcohol preservative compatibility and stability data. https://www.ashp.org/products-and-services/database-tools/handbook-on-injectable-drugs
- United States Pharmacopeia. (2024). Bacteriostatic Water for Injection — monograph and in-use stability guidance. USP-NF. (See institutional access.) https://doi.org/10.4135/9781412963855.n1200
- Wang, W. (1999). Instability, stabilization, and formulation of liquid protein pharmaceuticals. International Journal of Pharmaceutics, 185(2), 129–188. https://doi.org/10.1016/s0378-5173(99)00152-0
The arithmetic needs no citation; the diluent and stability guidance does.