Enter the three numbers you already have and read the exact mark to draw on a U-100 insulin syringe. This tool converts a dose you were given into units. It never suggests a dose.
Concentration is the peptide mass divided by the water you added: a 5 mg vial in 2 mL is 2.5 mg/mL. On a U-100 insulin syringe, 100 units equals 1 mL, so each unit holds 1/100 mL. Multiply concentration by that and you get the mass per unit; divide your dose by mass-per-unit and you get the number of units to draw. That is the entire calculation, and it is the same arithmetic regardless of which peptide is in the vial.
A tenfold error — reading 25 units as 2.5, or adding 0.2 mL instead of 2 mL — changes the delivered amount by 10 times. The calculator flags draws that exceed a full syringe and draws too small to measure, but it cannot see your vial. Confirm every number, and confirm the dose itself with a licensed provider.
It will not tell you what dose to take. For most research peptides there is no validated human dose to calculate from, so any number generated from your age or weight would be invented. That is the one thing we refuse to fake.