Work out the concentration of a reconstituted peptide vial and how many units to draw on an insulin syringe for any target dose. Used routinely with research peptides like BPC-157, ipamorelin, and tirzepatide.
The total mg of compound in the vial as labelled by the supplier.
How much sterile bac water you'll add to reconstitute the vial.
How much of the compound you want to take per injection.
U-100 syringes use the standard 100 units = 1 ml gradation.
The calculator uses the same volumetric logic any pharmacist would. Given the mass of compound in a vial and the volume of bacteriostatic water you add, the resulting concentration is simply:
concentration (mg/ml) = vial mass (mg) / water added (ml)
From there, the volume you need for any target dose follows the same way:
draw volume (ml) = dose (mg) / concentration (mg/ml)
Insulin syringes use the U-100 standard, where 100 units of the syringe correspond to 1 ml. So once you know the volume to draw, the unit count is just:
units (U-100) = draw volume (ml) × 100
For the canonical worked example — a 10 mg vial in 2 ml of bac water dosed at 250 mcg — that gives a 5 mg/ml concentration, a 0.05 ml draw, and a 5 unit mark on the syringe.
Some suppliers print “use X units” on the label assuming a specific reconstitution volume. If you add a different volume of water, the unit count changes — which is exactly what this calculator is for. Always trust the math against the actual volume you added, not a generic label.