Three Numbers, One Draw
Every reconstitution problem reduces to three values: how much peptide is in the vial, how much bacteriostatic water you add, and how large a dose you want. From those, a calculator derives concentration, milliliters to draw, and insulin-syringe units.
Concentration First
Concentration = peptide amount ÷ water volume. Add 2 mL of water to a 5 mg vial and you have 2.5 mg/mL (2,500 mcg/mL). Change the water and the concentration moves — the total peptide does not.
Dose → Volume → Units
Divide the target dose by concentration to get milliliters. On a U-100 scale, multiply milliliters by 100 to get units. That is why a 0.10 mL draw is 10 units on every U-100 barrel size.
Why Barrel Size Still Matters
30-, 50-, and 100-unit syringes share the same unit math, but mark spacing differs. Smaller barrels make tiny draws easier to hit precisely.
Use the on-site calculator to experiment with water volumes until your dose lands on a clean mark.
Educational and research framing only. Not medical advice.