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TB-500 Reconstitution Calculator

A synthetic version of a fragment of thymosin beta-4, a protein involved in cell migration and repair. Enter your vial size, the water you add, and your dose to see the units to draw. Defaults: 5 mg vial, 2 mL water, 2.5 mg per dose.

Math only. The dose itself comes from your prescriber or protocol; this page does not recommend one.

Excel: the button above exports this calculation as a spreadsheet with live formulas, or download the blank template.

How to reconstitute TB-500

TB-500 is sold as a freeze-dried powder, most often in 2 mg, 5 mg, 10 mg vials. Add bacteriostatic water, let it dissolve without shaking, and the concentration is the vial amount divided by the water: 5 mg in 2 mL is 2.5 mg/mL. On a U-100 insulin syringe one unit is 0.01 mL, so each unit carries 25 mcg, and a 2.5 mg dose is 100 units.

Not approved for human use. Commonly cited protocols use 2 to 5 mg twice a week for a loading period, then less often. Nothing on this page is a dosing recommendation; the calculator converts a dose you already have into syringe units.

TB-500 doses in syringe units (5 mg vial, 2 mL water)

DoseUnitsmLDoses per vial
2 mg800.82
2.5 mg10012
5 mg20021

Vial sizes at 2.5 mg per dose

VialWaterConcentrationUnits per doseDoses
2 mg2 mL1 mg/mL2500
5 mg2 mL2.5 mg/mL1002
10 mg2 mL5 mg/mL504

The dose column is in mg. Doubling the water halves the concentration and doubles the units per dose; the number of doses in the vial never changes. If a dose comes out under 5 units, use less water so it is easier to measure. If it exceeds the syringe, use more water or a bigger syringe.

Worked example

5 mg / 2 mL = 2.5 mg/mL = 2,500 mcg/mL. One unit = 0.01 mL = 25 mcg. 2,500 mcg / 25 mcg per unit = 100 units. The vial holds 5,000 / 2,500 = 2 doses, which at 2 per week is about 7 days.

See the general peptide calculator for the formulas, syringe sizes, and the common mg versus mcg mistakes.

Frequently asked questions

How many units is 2.5 mg of TB-500?

With 5 mg in 2 mL of bacteriostatic water the concentration is 2.5 mg/mL, each unit holds 25 mcg, and 2.5 mg is 100 units (1 mL). Change the water and the units change with it.

How much bacteriostatic water do I add to a 5 mg vial of TB-500?

Any volume gives the same doses; 2 mL is a common choice because it keeps 2.5 mg at 100 units, which is easy to read on an insulin syringe. Use the calculator's round-number table to pick a volume that fits your syringe.

How long does a 5 mg vial of TB-500 last?

At 2.5 mg per dose the vial holds 2 doses. At 2 doses a week that is about 7 days. Reconstituted vials are usually refrigerated and used within about four weeks.

What is the TB-500 dose?

Not approved for human use. Commonly cited protocols use 2 to 5 mg twice a week for a loading period, then less often. This calculator only converts a dose you already have into syringe units.

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