Short answer: According to the US prescribing information, Mounjaro (tirzepatide) starts at 2.5 mg once a week for 4 weeks, then goes to 5 mg. If needed, the dose can go up in 2.5 mg steps after at least 4 weeks on the current dose, to a maximum of 15 mg a week. Your doctor decides which dose you stay on.

Key takeaways

  • Mounjaro has six dose steps: 2.5, 5, 7.5, 10, 12.5 and 15 mg, all once a week.
  • 2.5 mg is a starting dose, not a treatment dose: its job is to get your body used to the medicine.
  • Zepbound, the weight-management brand of tirzepatide, uses the same steps; its label lists 5, 10 and 15 mg as maintenance doses.
  • You stay on each step for at least 4 weeks; whether you move up is your doctor's call.
  • Your dose is the amount printed on your pen or vial; do not split it or raise it on your own.

Mounjaro does not have one fixed dose. Treatment starts low and is raised step by step under your doctor's supervision. This gradual increase is called titration. Its purpose is not to speed things up but to reduce digestive side effects such as nausea.

This page is for general information only and is not medical advice. Which dose you use and when it changes are decisions for your doctor alone.

Mounjaro dosage chart

Step Weekly dose Role in the prescribing information
1 2.5 mg Starting dose, first 4 weeks
2 5 mg First treatment dose
3 7.5 mg Possible step after at least 4 weeks on 5 mg
4 10 mg Possible step after at least 4 weeks on 7.5 mg
5 12.5 mg Possible step after at least 4 weeks on 10 mg
6 15 mg Maximum dose

There are at least 4 weeks between steps, so going from 2.5 mg to 15 mg takes about 20 weeks at the earliest. Not everyone needs the maximum dose, and many people stay on a lower step.

Mounjaro and Zepbound: same steps

In the US, Mounjaro is approved for adults with type 2 diabetes, and Zepbound is the tirzepatide brand approved for weight management. Both start at 2.5 mg for 4 weeks and rise in 2.5 mg steps after at least 4 weeks on a dose, up to 15 mg. The Zepbound label names 5 mg, 10 mg and 15 mg as maintenance doses. Which product and which dose fit you is a decision for your doctor. For the full list of brand names, see GLP-1 medication names.

Why start at 2.5 mg?

Tirzepatide slows how fast the stomach empties and makes you feel full for longer. Starting on a high dose would make nausea, vomiting and diarrhea much more likely. The 2.5 mg dose gives your body time to adjust; the prescribing information says it is meant for starting treatment, not as a long-term dose.

So it is normal not to see much change in the first four weeks. For more on timing, see when do GLP-1 injections start working.

When does the dose go up?

According to the prescribing information, the dose can be raised by 2.5 mg after at least 4 weeks on the current dose. Your doctor decides whether to do that based on how you are responding, any side effects and your overall health. If a step is hard to tolerate, staying on it longer is also an option.

Nausea and other digestive side effects can come back for a few days after each increase. Why that happens is explained in what happens when your GLP-1 dose goes up.

What does the "mg" on the pen mean?

The number on the label is the weekly dose that pen or vial delivers. In the US, Mounjaro pens and vials are single-dose: one pen or one vial is one injection, and a carton of four covers four weeks. When your dose changes, you are usually prescribed pens or vials of the new strength.

Splitting a dose or drawing a different amount is not a use described in the prescribing information. Talk to your doctor about any change to your dose.

Keeping track of your step

Writing down how many weeks you have been on each step and how you felt after each increase makes it easier to answer your doctor's questions at a check-up. Haftra keeps your dose, injection day and symptoms together. It does not suggest doses or work out dose steps. It is free.

iPhone, iPad and Apple Watch. Free.

Frequently asked questions

What is the starting dose of Mounjaro?

According to the prescribing information, 2.5 mg once a week for 4 weeks, then 5 mg.

What is the highest dose of Mounjaro?

The maximum dose is 15 mg once a week.

Does Mounjaro 2.5 mg cause weight loss?

2.5 mg is a starting dose meant to get your body used to the medicine. The prescribing information does not describe it as a treatment dose, so any change at this step may be small.

Do you have to increase the Mounjaro dose every month?

No. At least 4 weeks on each step is a minimum, not a fixed schedule. Your doctor decides whether and when to move up, and many people stay below 15 mg.

When is Mounjaro 7.5 mg used?

7.5 mg is the step between 5 mg and 10 mg. After at least 4 weeks on 5 mg, your doctor may move you to it if needed.

Sources

  • FDA - Mounjaro (tirzepatide) prescribing information
  • FDA - Zepbound (tirzepatide) prescribing information
  • U.S. Food and Drug Administration (FDA)

Last reviewed: September 26, 2026