Reconstitution and syringe units
Tirzepatide Calculator
Convert a tirzepatide dose in mg into units on a U-100 syringe, for any vial size and concentration.
Tirzepatide calculator
Example values are loaded. Replace them with the numbers on your own vial.
Approved tirzepatide and where this math applies
Tirzepatide is FDA-approved as Mounjaro (type 2 diabetes) and Zepbound (weight management and obstructive sleep apnea). It acts on the GIP and GLP-1 receptors. Branded vials and pens arrive already in solution at a fixed strength, so they need no reconstitution. This calculator is for compounded or lyophilized vials, and for converting any mg dose into syringe units when you know the concentration.
Label dose steps
According to the Zepbound prescribing information, treatment starts at 2.5 mg once weekly for 4 weeks, then increases in 2.5 mg steps after at least 4 weeks on each dose. Maintenance doses are 5, 10 or 15 mg weekly, and the maximum is 15 mg weekly. Your prescriber sets your dose.
Units chart: 10 mg/mL
A 20 mg vial with 2 mL of water, or a 10 mg vial with 1 mL, gives 10 mg/mL. Each unit holds 0.1 mg.
| Dose | Units (U-100) | mL |
|---|---|---|
| 2.5 mg | 25 | 0.25 |
| 5 mg | 50 | 0.5 |
| 7.5 mg | 75 | 0.75 |
| 10 mg | 100 | 1 |
| 12.5 mg | 125 | 1.25 |
| 15 mg | 150 | 1.5 |
Units chart: 5 mg/mL
A 10 mg vial with 2 mL of water gives 5 mg/mL. This matches the concentration of branded single-dose vials (for example 2.5 mg in 0.5 mL).
| Dose | Units (U-100) | mL |
|---|---|---|
| 2.5 mg | 50 | 0.5 |
| 5 mg | 100 | 1 |
| 7.5 mg | 150 | 1.5 |
| 10 mg | 200 | 2 |
| 12.5 mg | 250 | 2.5 |
| 15 mg | 300 | 3 |
Pre-mixed compounded vials
If your vial is already liquid, the label gives a concentration such as "10 mg/mL". Enter that as a vial of 10 mg with 1 mL of water and the calculator gives the correct units. Always check whether the label states mg per mL or total mg per vial.
Frequently asked questions
How many units is 2.5 mg of tirzepatide?
At 10 mg/mL, 2.5 mg is 25 units. At 5 mg/mL, it is 50 units. Check the concentration on your vial.
How many units is 5 mg of tirzepatide?
At 10 mg/mL, 5 mg is 50 units. At 5 mg/mL, it is 100 units, a full 1 mL syringe.
What is the maximum tirzepatide dose on the label?
The Zepbound label lists 15 mg once weekly as the maximum dose.