Peptide Reconstitution Calculator

Reconstitution just means dissolving a lyophilized (freeze-dried) peptide in liquid so you can draw and inject it. The liquid is almost always bacteriostatic water - sterile water with a small amount of benzyl alcohol that keeps it usable for multiple draws.

The only thing that matters mathematically is the ratio: the milligrams in your vial divided by the milliliters of water you add gives your concentration in mg/mL. From there, your dose in milligrams divided by that concentration gives the volume you draw, which you can read straight off the units on an insulin syringe.

There is no single right answer - the amount of water you add sets your concentration, not your dose. Adding 2 mL to a 10 mg vial gives 5 mg/mL; adding 1 mL gives 10 mg/mL. A more dilute mix means more units on the syringe per dose (easier to measure small doses accurately); a more concentrated mix means fewer units.

For a 15 mg or 30 mg tirzepatide vial the same rule holds: 30 mg in 3 mL is 10 mg/mL. Use the calculator above to pick the water volume that lands your dose on an easy-to-read number of units.

Again, the water volume you choose sets the concentration. A 5 mg semaglutide vial with 1 mL of BAC water is 5 mg/mL; the same vial with 2 mL is 2.5 mg/mL. A 10 mg vial with 2 mL is 5 mg/mL.

Because semaglutide doses are often small, many people add enough water that a dose lands on a comfortable, readable number of units rather than a tiny sliver near the needle. Enter your vial size and target dose above to see exactly where each option lands.

A 10 mg retatrutide vial follows the same math as any other peptide. Add 2 mL of bacteriostatic water for 5 mg/mL, or 1 mL for 10 mg/mL.

The calculator converts whatever water volume you pick into a concentration, then shows the draw volume and units for the dose you enter.

A 5 mg BPC-157 vial reconstituted with 2 mL of bacteriostatic water is 2.5 mg/mL, or 250 mcg per 0.1 mL. A 10 mg vial with 2 mL is 5 mg/mL.

Research peptides like BPC-157 and TB-500 are frequently dosed in micrograms, so use the mcg toggle on the calculator - it normalizes everything to milligrams internally and shows you the units to draw.

TB-500 uses the identical ratio math. A 5 mg vial in 2 mL is 2.5 mg/mL; a 10 mg vial in 2 mL is 5 mg/mL.

Pick the water volume that puts your intended dose on a clean number of units. The calculator above does that conversion instantly and warns you instead of showing a broken result if a value is missing or zero.

A standard U100 insulin syringe is marked so that 1 mL equals 100 units. So if your draw volume works out to 0.25 mL, that is 25 units on the syringe. Multiply your draw volume in mL by 100 to get units on a U100 syringe.

If you use a U50 or U40 syringe, the units-per-mL differ - open the advanced toggle in the calculator and pick your syringe scale so the units readout matches your barrel.