How Many Doses Are in a Tirzepatide Vial?

To calculate how many weekly doses a tirzepatide vial contains, you need two pieces of information from your vial label: the concentration (mg/mL) and the total volume (mL). Multiply them together to get the total milligrams in the vial, then divide by your weekly dose.

total mg = concentration (mg/mL) x volume (mL) number of doses = total mg / weekly dose (mg)

For example, a 2 mL vial at 20 mg/mL contains 40 mg total. If your weekly dose is 10 mg, that vial covers 4 weeks of treatment.

Here are common compounded tirzepatide vial configurations and how many weeks they last at various doses:

2 mL vial at 10 mg/mL (20 mg total): 2.5 mg/week = 8 weeks 5 mg/week = 4 weeks 10 mg/week = 2 weeks

2 mL vial at 20 mg/mL (40 mg total): 5 mg/week = 8 weeks 10 mg/week = 4 weeks 15 mg/week = 2.67 weeks (approximately 2 weeks + 5 days)

5 mL vial at 10 mg/mL (50 mg total): 5 mg/week = 10 weeks 10 mg/week = 5 weeks 15 mg/week = 3.3 weeks

5 mL vial at 20 mg/mL (100 mg total): 5 mg/week = 20 weeks 10 mg/week = 10 weeks 15 mg/week = 6.67 weeks

Note that your pharmacy may dispense different vial sizes. Always check the label for both concentration and total volume.

Knowing how many doses are in your vial helps you plan refills, manage costs, and avoid running out of medication. If your vial covers four weeks and your dose escalation is scheduled to increase at week four, you will need a new vial (potentially at a different concentration) when you move to the higher dose.

It also helps you understand the cost per dose. If a 2 mL vial at 20 mg/mL costs $350 and lasts four weeks at 10 mg/week, your per-week cost is approximately $87.50. A larger vial may have a higher upfront cost but a lower per-dose cost. Talk to your provider or pharmacy about which vial size makes the most financial sense given your current dose and expected escalation timeline.

Compounded tirzepatide vials are multi-dose, meaning you draw multiple injections from the same vial over several weeks. Once punctured, most compounded vials have a beyond-use date (BUD) of 28 to 90 days depending on the pharmacy's formulation and preservatives used. Check your vial label or pharmacy documentation for the specific BUD.

If your vial contains more doses than you can use before the BUD expires, the remaining medication should be discarded. For example, a 5 mL vial at 20 mg/mL at a 5 mg weekly dose theoretically lasts 20 weeks, but if the BUD is 60 days, you would only get about 8 weeks of use. Factor this into your refill planning and discuss vial sizing with your provider.

Store opened vials according to your pharmacy's instructions -- typically refrigerated between 36-46 degrees Fahrenheit (2-8 degrees Celsius). Do not freeze compounded vials, and keep them away from direct sunlight. Proper storage helps ensure the medication remains effective through the beyond-use date.