Switching from Wegovy to Mounjaro

Wegovy and Mounjaro are popular weight loss injections that work in a similar way. Since Mounjaro is the most effective weight loss injection available, some people are keen to switch to it from Wegovy.

In this guide, we’ll explore how you can switch from Wegovy to Mounjaro, why you may want to, and what you can expect once you have switched medications.

Yes, switching from Wegovy to Mounjaro is possible if you meet the prescribing guidelines required to take both medications. As these are almost identical, you’re likely to be able to take Mounjaro if you already take Wegovy.

Before you switch, your doctor will check that you meet one of the following criteria:

1. You have a body mass index (BMI) between 27 and 29.9 with a weight-related health condition.
2. You have a BMI of at least 30.

After discussing switching from Wegovy to Mounjaro with your doctor:

1. Stop taking Wegovy when your last pen is finished.
2. You should wait 7 days before starting Mounjaro to allow enough time for Wegovy to leave your system. These medications can interact and cause unwanted side effects if taken too close together.
3. After 7 days, start your first dose of Mounjaro, then continue taking your injections once a week on the same day and time, just like you did with Wegovy. Which dose you’ll start on will depend on what dose of Wegovy you were on, and whether you had any side effects.

This table shows the maximum Mounjaro dose you can start on when switching from your current dose of Wegovy:

For more information on Mounjaro dosages for weight loss, take a look at our guide.

There are a few reasons why some people choose to switch from Wegovy to Mounjaro, including:

Effectiveness

Clinical trials show that Mounjaro is associated with greater weight loss. At the highest maintenance dose of 15mg per week, Mounjaro helps people lose an average 22.5% of their initial body weight. At the highest Wegovy dose of 2.4mg per week, people can lose an average of 15% of their starting weight after 68 weeks.

Side effects

Both weight loss injections can cause side effects but if you’re experiencing adverse effects on Wegovy, you may want to switch to Mounjaro. However, there is no guarantee that you will not experience Mounjaro side effects if you switch because everybody reacts differently to medications.

Results

If you are not experiencing the weight loss you’d hoped for while using Wegovy, you may want to switch to Mounjaro. If you have not lost at least 5% of your starting weight within 6 months of starting Wegovy, your doctor may suggest that you stop using it.

Anyone who meets the criteria for both weight loss medications can make the switch from Wegovy to Mounjaro.

If you are already taking Wegovy, you will likely be able to use Mounjaro. Your doctor will check that you meet the following eligibility criteria before helping you to swap medications:

• a BMI between 27 and 30 with a weight-related condition such as high blood pressure, prediabetes, or obstructive sleep apnoea or a BMI of 30 or more
• not breastfeeding or pregnant
• have no pre-existing medical conditions that mean Mounjaro is unsuitable for you, such as an allergy to the active ingredient, tirzepatide
• over 18 years old
• not taking any medications which may interact with Mounjaro

When you switch from Wegovy to Mounjaro, you may notice some changes in your appetite as Wegovy leaves your system. For example, you may notice that your appetite increases in the short term because semaglutide will no longer bind to the receptors in your brain that signal that you feel full.

However, this will be a temporary effect because Mounjaro works in the same way as Wegovy by binding to the glucagon-like peptide-1 (GLP-1) receptors, so you should notice positive changes to your appetite as your Mounjaro dose increases.

When you switch, it is unlikely that you will experience Wegovy withdrawal symptoms but you may notice appetite changes, body changes, or stomach upset. Rather than withdrawal symptoms, these are signs your body is returning to its baseline.

As your dose of Mounjaro titrates up and your body gets used to the medication, you are more likely to notice better weight loss results.

The simple answer is yes – if you are suitable for Mounjaro treatment, you should consider switching from Wegovy to Mounjaro. That’s because Mounjaro is often a better weight loss option and is associated with greater weight loss.

If you are interested in making the change from Wegovy to Mounjaro, you can begin a consultation with one of our doctors to see if Mounjaro is suitable for you:

Find out more about Mounjaro before switching:

• Mounjaro KwikPen 10mg solution for injection in pre-filled pen, emc [accessed 20 August 2025]
• Once-Weekly Semaglutide in Adults with Overweight or Obesity, NEJM [accessed 20 August 2025]
• Tirzepatide Once Weekly for the Treatment of Obesity, The New England Journal of Medicine [accessed 20 August 2025]
• Wegovy 0.25 mg, FlexTouch solution for injection in pre-filled pen, emc [accessed 20 August 2025]
• Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension, Diabetes, Obesity & Metabolism [accessed 20 August 2025]