Peptide Reconstitution Calculator

Using it in four steps

1. Vial mass. Enter how many milligrams of lyophilized peptide the vial holds, or tap a preset.
2. Diluent volume. Enter the millilitres of bacteriostatic water added. This sets the concentration and nothing else.
3. Target per draw. Enter the amount you want each withdrawal to contain, in micrograms or milligrams.
4. Read the barrel. The meter shows where that volume falls on a U-100 syringe, with the exact figures beneath it.

How reconstitution math works

Reconstitution is simply dissolving a lyophilized (freeze-dried) research peptide in bacteriostatic water so it can be measured by volume. The concentration is the vial mass divided by the water you add: a 10 mg vial in 2 mL of BAC water is 5 mg/mL. From there, any target draw is that amount divided by the concentration, and on a U-100 insulin syringe 1 mL reads as 100 units.

Worked example

10 mg vial ÷ 2 mL = 5 mg/mL. A 250 mcg target draw is 0.25 mg ÷ 5 mg/mL = 0.05 mL, which is 5 units on a U-100 barrel, giving 40 equal draws per vial. Change the water volume and the unit mark changes; the total peptide in the vial does not.

Bacteriostatic water

Most reconstitution references use bacteriostatic water (0.9% benzyl alcohol) for multi-draw storage. The amount of diluent does not change how much peptide is in the vial — only how far it spreads across the barrel, which changes how precisely small volumes can be measured.