Semaglutide Reconstitution Calculator
Reconstituting compounded semaglutide? Enter your vial size, your weekly dose, and how much bacteriostatic water you're adding — this free semaglutide reconstitution calculator shows the exact units to draw on an insulin syringe, your vial's concentration, and how many weekly doses the vial holds.
100 units per mL — pick the syringe you have.
Draw to
BAC water
on a U-100 insulin syringe
Drag the syringe to set your dose, or type the values above.
Enter your vial amount and dose, then type the bacteriostatic water or drag the syringe to see the exact units to draw.
Chips and prefilled values are commonly used numbers shown for convenience — not recommendations. Enter your own vial, dose, and water.
Never do this math twice.
The Pep AI app remembers your vials and doses, shows an interactive syringe you draw to, counts down the doses left in each vial, and reminds you when it's time. Free on iOS and Android.
How semaglutide reconstitution works
Compounded semaglutide usually arrives as a dry (lyophilized) powder that you mix with bacteriostatic water before injecting. Three steps turn your numbers into a syringe draw:
1. Concentration
Vial amount ÷ water added. A 10 mg vial with 2 mL of water is 5 mg/mL.
2. Volume per dose
Your dose ÷ concentration. A 0.5 mg dose at 5 mg/mL is 0.1 mL.
3. Units to draw
Volume per dose × 100 for a U-100 syringe (or × 40 for a U-40). 0.1 mL on a U-100 syringe is 10 units.
Worked example
You have a 10 mg vial, you want a 0.5 mg dose, and you add 2 mL of bacteriostatic water. Concentration is 10 ÷ 2 = 5 mg/mL. Volume per dose is 0.5 ÷ 5 = 0.1 mL. On a U-100 syringe that's 0.1 × 100 = 10 units, and the vial holds 20 doses.
Reconstituting semaglutide, briefly
Brand-name semaglutide pens (Ozempic, Wegovy) come prefilled — no mixing involved. Reconstitution enters the picture with compounded semaglutide, which is typically dispensed as a lyophilized vial (2.5, 5, and 10 mg sizes are common) plus bacteriostatic water. Because semaglutide doses are small — prescription protocols run from 0.25 mg up to 2.4 mg weekly — each draw is a tiny volume, and the difference between doses can be just a few units on the syringe.
The other thing that catches people is titration. Prescription semaglutide steps up over months (0.25 → 0.5 → 1 → 1.7 → 2.4 mg on the Wegovy schedule), and every step changes the number of units to draw from the same vial. Whenever your dose changes, the units change with it — recalculate rather than remembering "my dose is 10 units."
If you're on semaglutide long-term, the Pep AI app saves your vial and reconstitution details, converts every dose to units automatically, counts the doses left in the vial, and reminds you on shot day — see the semaglutide tracker for the full picture.
Frequently asked questions
This calculator is provided for informational and educational purposes only and is not medical advice. Always confirm dosing with a qualified healthcare professional and double-check your own measurements before administering anything.