Use this free tirzepatide dosage calculator to work out exactly how many units to draw for any dose. Enter your vial size, the water you added, and your target dose — the syringe graphic shows you where to draw to. Below the calculator you will find the standard weekly dosage chart and a worked example.
1 mL = 100 units on a U-100 syringe · 1 mg = 1000 mcg. For research and educational purposes only. Not medical advice.
Tirzepatide dosage chart (weekly schedule)
Tirzepatide is increased slowly, usually every 4 weeks. The standard titration schedule used in research settings is:
| Weeks | Weekly dose |
|---|---|
| Weeks 1–4 | 2.5 mg |
| Weeks 5–8 | 5 mg |
| Weeks 9–12 | 7.5 mg |
| Weeks 13–16 | 10 mg |
| Weeks 17–20 | 12.5 mg |
| Week 21 onwards | 15 mg (maximum) |
How many units that is depends on your vial and how much water you added. Example: a 10 mg vial mixed with 2 mL of bacteriostatic water (5 mg/mL): 2.5 mg = 50 units, 5 mg = 100 units. For any other dose or vial size, use the calculator above.
How to use this calculator
- Pick your syringe size. The 1 mL (100-unit) insulin syringe is the most common choice, while smaller 0.5 mL (50-unit) and 0.3 mL (30-unit) syringes give finer control when measuring small doses.
- Enter the vial quantity. Type in the amount of tirzepatide printed on the vial label, in mg; common vial sizes are 10 mg, 20 mg and 30 mg.
- Enter the water volume. Add the amount of bacteriostatic water mixed into the vial, in mL, since this number sets the concentration shown in your results.
- Enter the wanted dose. Type the dose in either mg or mcg, and the calculator converts between the two units automatically.
- Read the result. The result sentence states the exact number of units to draw on your chosen syringe, and the syringe graphic fills to the matching dose mark so you can check it visually.
Frequently asked questions
How many units is 2.5 mg of tirzepatide?
It depends on concentration. With a 10 mg vial mixed with 2 mL of water (5 mg/mL), 2.5 mg is 50 units. With 1 mL of water (10 mg/mL), it is 25 units. Enter your own numbers in the calculator for an exact answer.
What is the starting dose of tirzepatide?
Research protocols start at 2.5 mg once weekly for the first 4 weeks, then increase by 2.5 mg every 4 weeks as needed, up to 15 mg weekly.
How long does a 10 mg vial last?
At 2.5 mg per week, one 10 mg vial holds 4 weekly doses. At 5 mg per week, it holds 2 doses. The calculator shows doses per vial for your numbers.
How should reconstituted tirzepatide be stored?
Keep it refrigerated at 2–8 °C, do not freeze it, and use it within the timeframe given by your supplier, commonly 4 weeks after mixing.
For research and educational purposes only. Tirzepatide is a prescription medication; this page is a calculation tool and dosage reference, not medical advice.