Short answer: In the standard schedule of the US prescribing information, Mounjaro (tirzepatide) starts at 2.5 mg once a week for 4 weeks, and the next step is 5 mg. The schedule allows increases in 2.5 mg steps after at least 4 weeks on the current dose, to a maximum of 15 mg a week. The prescriber decides the steps, the timing and whether to step up at all.

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.
  • According to the prescribing information, each step lasts at least 4 weeks; whether to move to the next one is the prescriber's decision.
  • The dose is the amount printed on the pen or vial; splitting or changing it is not a use described in the prescribing information.

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

The dosing decision is your doctor's. The table below reproduces the standard dose schedule in the US prescribing information; it is not a personal treatment plan. Which step to stay on, when to move and whether to step up at all is decided by the prescriber.

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

In the schedule there are at least 4 weeks between steps, so even the shortest path from 2.5 mg to 15 mg takes about 20 weeks. The prescribing information does not describe the maximum dose as a target for everyone; the maintenance dose is set by the prescriber.

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. Whether that happens is the prescriber's decision, based on the response, any side effects and overall health. When a step is not well tolerated, the prescriber may also decide to stay on it longer.

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. Any change to the dose is made together with the doctor.

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?

In the standard schedule of the prescribing information, the starting dose is 2.5 mg once a week for 4 weeks; the next step in the schedule is 5 mg. The prescriber decides when to move.

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. The prescribing information sets at least 4 weeks on each step, not a monthly requirement. Whether and when to move up is the prescriber's decision, and the maintenance dose can differ from person to person.

When is Mounjaro 7.5 mg used?

In the prescribing information schedule, 7.5 mg is the step between 5 mg and 10 mg. According to the schedule, it comes after at least 4 weeks on 5 mg; the prescriber decides on the move.

Sources

Last reviewed: October 15, 2026