Reconstitution and syringe units
TB-500 Calculator
Convert a TB-500 vial, the water added and an amount into units on a U-100 insulin syringe.
TB-500 calculator
Example values are loaded. Replace them with the numbers on your own vial.
TB-500 is not an approved medicine, and it is prohibited in sport by the World Anti-Doping Agency. Nothing on this page is a dose recommendation.
What is sold as TB-500
"TB-500" is a trade name, not a standard. It is sold as a synthetic peptide related to thymosin beta-4, a naturally occurring 43-amino-acid protein. Depending on the seller, the vial may contain a short fragment or a longer version, and they have very different molecular weights. That does not change the mg-based arithmetic here, but it does mean two vials called TB-500 may not contain the same thing. A certificate of analysis tells you what you actually have.
TB-500 was among the peptides the FDA removed from its Category 2 compounding list in April 2026. Removal from that list is not approval.
Units chart: 5 mg vial with 2 mL water
At 2.5 mg/mL, each unit holds 25 mcg (0.025 mg).
| Dose | Units (U-100) | mL |
|---|---|---|
| 250 mcg | 10 | 0.1 |
| 500 mcg | 20 | 0.2 |
| 1 mg | 40 | 0.4 |
| 2 mg | 80 | 0.8 |
| 2.5 mg | 100 | 1 |
| 5 mg | 200 | 2 |
Units chart: 10 mg vial with 2 mL water
| Dose | Units (U-100) | mL |
|---|---|---|
| 250 mcg | 5 | 0.05 |
| 500 mcg | 10 | 0.1 |
| 1 mg | 20 | 0.2 |
| 2 mg | 40 | 0.4 |
| 2.5 mg | 50 | 0.5 |
| 5 mg | 100 | 1 |
Large draws
Amounts in the milligram range can produce draws over 50 or 100 units at low concentrations. If a draw does not fit your syringe, less water raises the concentration and shrinks the draw. The calculator warns you when a draw exceeds the syringe you selected.
Frequently asked questions
How many units is 2 mg of TB-500?
In a 5 mg vial with 2 mL of water (2.5 mg/mL), 2 mg is 80 units. In a 10 mg vial with 2 mL (5 mg/mL), it is 40 units.
Is TB-500 the same as thymosin beta-4?
Not necessarily. Products sold as TB-500 may be a fragment of thymosin beta-4 or a longer version. Check the certificate of analysis.