Mounjaro and Wegovy are effective weight loss medications that have a similar mechanism of action. Recently, there has been a rise in the number of people using Mounjaro switching to Wegovy for reasons like side effects, higher costs, a change in their health goals, and sometimes, their clinician’s medical advice.
Irrespective of the reason, it is important to be aware of how to change medication and make the switch safely to ensure you do not lose your weight loss momentum and are able to avoid serious side effects.
In this article, we will cover how to switch safely from Mounjaro to Wegovy so that your weight-loss journey continues smoothly.
The Difference Between Mounjaro and Wegovy
Mounjaro and Wegovy are both weekly injections designed to help with weight management, but they’re not quite the same. Wegovy’s active ingredient is Semaglutide, while Mounjaro contains Tirzepatide. [1] [2]
Both drugs work as GLP-1 receptor agonists. In simple terms, they simulate the effects of the natural hormone GLP-1 that tells your brain when you’re full. They also slow down digestion, causing food to stay in your stomach longer. This helps you feel satisfied sooner, lowers food intake, and most importantly, keeps you from overeating.
The big difference in these two medications is that Mounjaro is a dual agonist. In addition to GLP-1, it works on another hormone called GIP. This dual mechanism results in more weight loss.
Studies have revealed that people taking Mounjaro lost about 22.9% of their body weight over 3.5 years, compared to about 16.7% over 2 years with Wegovy. [3] [4]
However, Mounjaro is more likely to cause severe side effects. In addition, it’s more expensive compared to Wegovy. In fact, the manufacturer of Mounjaro, Eli Lilly, has announced a nearly 170% price increase starting September 2025.
It’s important to consider these differences between Mounjaro and Wegovy when choosing the right medication suitable for you. A proper provider should be able to guide you through the right decision for your medical and financial needs.
Why Should I Switch from Mounjaro to Wegovy?
There are a few reasons why someone might change from Mounjaro to Wegovy.
Side effects are one of the biggest factors. It is reported that even though both medications cause similar issues like nausea or stomach upset, most people notice fewer problems with Wegovy compared to Mounjaro. In short, Wegovy is generally considered to be easier to tolerate than Mounjaro.
Adherence to your obesity treatment is another potential reason. If side effects from Mounjaro are slowing you down or making it hard for you to stick with treatment, switching to Wegovy could be an alternative to help you get back on track with your weight loss journey.
Heart health also plays a role in determining if you need to switch your medication. Wegovy is currently the only GLP-1 medication approved in the UK to lower the risk of major heart problems – like heart attacks or strokes – in people with obesity and existing heart disease.
And of course, there are practical reasons to switch. Sometimes supply shortages, changes in cost, or personal preference make one option more appealing than the other.
At the end of the day, the decision should always be focused on finding the treatment that works best for you.
How to Switch Safely to Wegovy?
Moving from Mounjaro to Wegovy is usually a smooth process as long as you follow guidance properly. Here are the steps on how to change medication to ensure a smooth transition:
- You’ll take your last dose of Mounjaro on your usual injection day.
- Then, the following week, on that same day, you’ll start your first dose of Wegovy. Follow the medical advice from your doctor about the exact timing and dose that’s right for you.
- From there, your Wegovy dose will slowly increase over time. This gradual step-up is called titration. It helps your body adjust while keeping side effects to a minimum.
For most people, the experience of switching feels very familiar. You’ll still be taking once-a-week injections, sticking to the same dosage schedule, and continuing healthy lifestyle habits to support your weight loss journey. Thankfully, the transition does not involve a long break in treatment, allowing your progress to continue uninterrupted.
In short, you will just be moving forward with a different medication. Think of it not as “starting over,” but as continuing the same journey with a new tool.
Do You Need a Break Between Medications?
A common question regarding how to change medication is whether you need to stop treatment before starting Wegovy.
The short answer is no.
There’s no “washout” period needed. You simply take your last Mounjaro dose, then start Wegovy the following week on your usual injection day.
So, if your injection day is Monday and you take your last Mounjaro dose on a Monday, you’ll start Wegovy the very next Monday. This way, you can switch safely, there are no gaps in treatment, and your weight loss momentum continues without interruption.
How is Wegovy Titrated?
Wegovy is increased gradually over time, in the same step-by-step way as Mounjaro. The usual schedule looks like this:
- Weeks 1-4: 0.25 mg once a week
- Weeks 5-8: 0.5 mg once a week
- Weeks 9-12: 1.0 mg once a week
- Weeks 13-16: 1.7 mg once a week
- Week 17 onwards: 2.4 mg once a week (maintenance dose)
The slow dosage adjustment in this manner will allow enough time for your body to adjust, lowering your chance of side effects. If you do get symptoms, your doctor can pause or delay the next dosage increment until you’re ready.
Are There Any Differences When Switching?
Mounjaro and Wegovy are very similar in terms of how they’re taken, but there are a couple of small differences to know about:
Priming the pen: With Wegovy, you only need to prime the pen before your very first injection. For every dose after that, no priming is needed. Mounjaro, on the other hand, requires priming before each injection.
Storage: Both medicines need to be refrigerated until first use. After that, Mounjaro can be stored at room temperature (up to 30°C) for 30 days, while Wegovy can stay at room temperature for up to 42 days.
Can I Start with A Higher Dose Of Wegovy?
Yes, you can start with a higher dose of Wegovy, instead of its lowest starting dose, when moving over from Mounjaro. In most cases, you should begin at a dose that’s closer to the level you were already taking with Mounjaro.
Some people still prefer to start on a lower Wegovy dose to ease side effects, and that’s an option too.
Here’s a guide to how Mounjaro doses usually match up with Wegovy:
- If you’re on 2.5 mg of Mounjaro, switch to 0.25 mg of Wegovy.
- If you’re on 5 mg of Mounjaro, switch to 0.5 mg of Wegovy.
- If you’re on 7.5 mg of Mounjaro, switch to 1 mg of Wegovy.
- If you’re on 10 mg of Mounjaro, switch to 1 mg of Wegovy.
- If you’re on 12.5 mg of Mounjaro, switch to 1.7 mg of Wegovy.
- If you’re on 15 mg of Mounjaro, you’ll usually switch to 1.7 mg of Wegovy.
You can contact our weight loss expert for medical advice on the best starting dose for you. They’ll look at your current Mounjaro dose, how well you’ve tolerated it, and the progress you’ve made so far to recommend the optimum dosage adjustment.
Also, even if you’re used to higher doses of Mounjaro, your provider may sometimes recommend starting with a slightly lower dose of Wegovy. This dosage adjustment is aimed at lowering the risk of side effects like nausea, bloating, or stomach discomfort, which are more common when changing medications.
Conclusion
Switching from Mounjaro to Wegovy can be a smooth and effective transition when managed carefully under the guidance of your doctor.
Whether you’re motivated by cost, insurance coverage, side effects, or availability, Wegovy offers a reliable alternative for long-term weight management. The key to successful transition lies in maintaining continuity, careful titration, and lifestyle support.
At The Virtual Slimming Clinic, we provide prescribed doses of both Mounjaro and Wegovy, depending on your individual weight loss needs. Wherever your starting point is, we offer proper medical advice on beginning the process, along with making sure you can make a seamless switch safely.
Beyond this, we also have a blog, full of insights that can aid you with the momentum of your weight-loss journey. Check out our articles for accurate, actionable guidance on everything from medication to more traditional weight loss steps.
