At a glance
| Mark on U-100, 1 mL | Volume | at 4.17 mg/mL Zepbound 10 mg multi-dose vial | at 5 mg/mL Zepbound 2.5 mg single-dose vial | at 8.33 mg/mL Zepbound 20 mg multi-dose vial | at 10 mg/mL | at 12.5 mg/mL Zepbound 30 mg multi-dose vial | at 20 mg/mL |
|---|---|---|---|---|---|---|---|
| 10 units | 0.1 mL | 0.417 mg | 0.5 mg | 0.833 mg | 1 mg | 1.25 mg | 2 mg |
| 20 units | 0.2 mL | 0.834 mg | 1 mg | 1.67 mg | 2 mg | 2.5 mg | 4 mg |
| 25 units | 0.25 mL | 1.04 mg | 1.25 mg | 2.08 mg | 2.5 mg | 3.13 mg | 5 mg |
| 30 units | 0.3 mL | 1.25 mg | 1.5 mg | 2.5 mg | 3 mg | 3.75 mg | 6 mg |
| 40 units | 0.4 mL | 1.67 mg | 2 mg | 3.33 mg | 4 mg | 5 mg | 8 mg |
| 50 units | 0.5 mL | 2.08 mg | 2.5 mg | 4.17 mg | 5 mg | 6.25 mg | 10 mg |
| 60 units | 0.6 mL | 2.5 mg | 3 mg | 5 mg | 6 mg | 7.5 mg | 12 mg |
Arithmetic at the concentrations shown. The concentration on your own label is the one that counts; enter it in the calculator.
Why the milligrams depend on the label
This is the usual question turned around, and people usually ask it because someone told them a number of units rather than a dose in milligrams. The arithmetic is the reverse of the dose-to-units conversion. First turn the mark into a volume: on a U-100 syringe, units divided by 100 is millilitres, so 20 units is 0.2 mL. Then multiply that volume by the concentration on your vial. For the labelled Zepbound presentations the concentrations are fixed, so 0.2 mL of the 10 mg multi-dose vial (4.17 mg/mL) is about 0.83 mg, and 0.2 mL of the 30 mg multi-dose vial (12.5 mg/mL) is 2.5 mg. For a compounded vial the concentration is whatever the pharmacy printed on the label, and the result can differ by several times between pharmacies. Note that the labelled Zepbound multi-dose withdrawal is 0.6 mL, the 60 mark, not 20 units; if you were told 20 units for a Zepbound vial, check the instruction with your pharmacist before drawing.
The mistake to watch for. "20 units" from a friend on a different pharmacy's vial is not your 20 units. The same mark holds a different milligram amount at a different concentration. Compare doses in milligrams, not marks.