Work out your concentration, draw volume and total doses — with a visual syringe guide.
A vial contains a fixed amount of peptide powder. Adding bacteriostatic (BAC) water doesn't change the total potency — it only changes the concentration, i.e. how much fluid you draw to hit a given dose.
The formula is simple: Volume to draw = Target dose ÷ Concentration, where Concentration = Total peptide ÷ Water added. On a U-100 insulin syringe, 1 unit = 0.01 mL, so 1 mL = 100 units.