Short answer: In the standard schedule of the product 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. Your GP or 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 weight-loss dose: its job is to get your body used to the medicine.
  • The product information lists 5, 10 and 15 mg as maintenance doses.
  • According to the product information, each step lasts at least 4 weeks; whether to move to the next one is the prescriber's decision.
  • The dose is the one printed on the pen; splitting or changing it is not a use described in the product information.

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

This page is for general information only and does not replace medical advice. Which dose you use and when it changes are decisions for your GP or prescriber alone.

Mounjaro dose chart

The dosing decision is your doctor's. The table below reproduces the standard dose schedule in the product information (summary of product characteristics); 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 your GP or prescriber.

Step Weekly dose Role in the product information
1 2.5 mg Starting dose, first 4 weeks
2 5 mg First maintenance dose
3 7.5 mg In-between step
4 10 mg Maintenance dose
5 12.5 mg In-between step
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 product information does not describe the maximum dose as a target for everyone; the maintenance dose is set by the prescriber.

Why start at 2.5 mg?

Tirzepatide slows how quickly the stomach empties and keeps you feeling full for longer. Starting on a high dose would make nausea, vomiting and diarrhoea much more likely. The 2.5 mg dose lets your body adjust; the product information does not list it as a maintenance dose for weight management.

So it is normal not to see much change on the scales in the first four weeks. More on this in when do weight-loss injections start working.

When does the dose go up?

According to the product 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 how weight is changing, any side effects and general health. When a step is not well tolerated, the prescriber may also decide to stay on it for longer.

Nausea and other digestive side effects can return for a few days after each increase. Why that happens is explained in what happens when your weight-loss injection dose goes up.

What does the "mg" on the pen mean?

The number on the KwikPen label is the weekly dose that pen gives. Each KwikPen holds several doses of the same strength. When your dose changes, you are usually prescribed a pen of the new strength.

Taking a different amount from a pen by splitting doses or counting clicks is not a use described in the product information. Any change to the dose is made together with the prescriber.

Keeping track of your step

Noting how many weeks you have been on each step and how you felt after each increase makes it easier to answer your prescriber's questions at a review. 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 product 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.

Do you lose weight on Mounjaro 2.5 mg?

2.5 mg is a starting dose to get your body used to the medicine, and the product information does not list it as a maintenance dose for weight management. Any change on this step may be small.

Do you have to go up a Mounjaro dose every month?

No. The product 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 product information schedule, 7.5 mg is the in-between step from 5 mg to 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: 15 October 2026