Reconstitution math

Let's work a real example. Say you have 5 mg of powder in your vial and your target dose is 250 mcg. What happens when you reconstitute with 2 mL of water?

5 mg of powder + 2 mL of water = 5,000 mcg in 200 units of BAC water

To find the concentration of a single unit, divide the total by the units of water.

5,000 mcg / 200 units = 25 mcg per unit

Since your dose is 250 mcg, you draw to 10 units. That's the math.

The amount of water you add changes that concentration, which changes how many units you draw for the same 250 mcg dose. Here is the same 5 mg vial reconstituted five different ways.

• 1 mL = 50 mcg per unit = 5 units for a 250 mcg dose
• 2 mL = 25 mcg per unit = 10 units
• 3 mL = 16.67 mcg per unit = 14.99 units
• 4 mL = 12.5 mcg per unit = 20 units
• 5 mL = 10 mcg per unit = 25 units

At 3 mL you would draw to 14.99 units, which is an awkward number to read on a syringe. Choosing 1, 2, 4, or 5 mL instead lands your dose on a clean, round number of units.

Our reconstitution calculator does this for you. Give it the amount of powder in your vial, the amount of BAC water you added, and your target dose. It will tell you how many units to draw.