Wegovy and Mounjaro are both used to help people lose weight, and they work in very similar ways. Usually, patients will stick with one or the other, but sometimes, people consider switching from Wegovy to Mounjaro under clinical supervision.
We’ll explore when switching might make sense, what sets these two weight-loss medications apart from each other, and how to go about switching safely in a way that will help you on your weight loss journey.
Why some people might consider making a treatment change
First of all, due to response variability, not everyone responds the same way to medications. We’re all different, and some people might find, for example, that they’re struggling with Wegovy side effects and want to see if Mounjaro might be a better fit.
Another major reason why people may want to switch is that Mounjaro might be more effective than Wegovy at higher doses – though individual results can vary. So, if someone has hit a plateau on Wegovy, they might decide to try Mounjaro instead.
Both medications are GLP-1 receptor agonists, meaning that they mimic the hormone GLP-1, which reduces appetite and slows digestion, making people feel fuller for longer. But they contain different active ingredients. Wegovy contains semaglutide, whereas Mounjaro contains tirzepatide.
Not only that, but Mounjaro also mimics another hormone, GIP. It works with GLP-1 to change how some fat is stored in the body, and it might help boost metabolism, too.
This may explain why some people see greater weight loss on Mounjaro. A clinical trial published in 2025 indicated that people on Mounjaro lost 20.2% of their body weight, while people on Wegovy lost 13.7% of their body weight.
Meanwhile, those taking Mounjaro saw their waist sizes reduce by over five centimetres (around two inches) more on average than those on Wegovy.
So, if people aren’t seeing the weight loss they hoped for on Wegovy, they might want to give Mounjaro a try.
Meanwhile, Wegovy was approved by the Medicines and Healthcare products Regulatory Agency (MHRA) a couple of months earlier than Mounjaro. So, if someone started on Wegovy before they had the chance to try Mounjaro, they may want to change.
What to consider before you switch Wegovy to Mounjaro
To switch from Wegovy to Mounjaro, you must ensure that you’re eligible. If you meet the criteria for Wegovy, you’re likely to be eligible for Mounjaro, though it’s important to note that if you have a known allergy to the active ingredient, tirzepatide, you won’t be able to.
Whereas people usually need to have a BMI of 30 or over, or 27 or over along with weight-related health conditions, people can often switch from one to the other, even if they’ve already reached a healthy BMI.
Switching involves speaking to your clinician and following the instructions they give you. You’ll likely need to follow a process like the one outlined here:
- Stop taking Wegovy when your last pen is finished. Or, if you’re switching because of the side effects and you don’t want to finish your medication, you may decide to stop straight away.
- Wait seven days, and then begin taking Mounjaro. This is the same amount of time you’d wait between Wegovy injections usually, so it shouldn’t be too disruptive to your routine. It allows the semaglutide to leave your system before you start a new GLP-1.
Can I start on a higher Mounjaro dose?
There’s no official guidance from the Medicines and Healthcare products Regulatory Agency (MHRA) or the National Institute for Health and Care Excellence (NICE), but the safest plan of action is to start Mounjaro at the lowest available dose and gradually increase per the standard schedule.
Even if you were on a higher dose of Wegovy, Mounjaro usually starts at the lowest available dose to reduce the risk of side effects – your clinician may be able to advise whether a higher starting dose is appropriate.
The switch from Wegovy to Mounjaro may be a good idea for some patients, but equally, it won’t be right for everyone. If it’s something you’re considering, it’s best to get professional guidance and support from a clinician. Discussing things with an expert like those at The Virtual Slimming Clinic can help you make the right decision for you, and support you as your weight loss journey continues.
Frequently asked questions
Why might someone decide to switch from Wegovy to Mounjaro?
They might not see the weight loss they were hoping for on Wegovy. Because some people lose more weight on Mounjaro at higher doses, they may decide that switching as part of a treatment change could give them a better chance of losing more weight.
Are side effects worse on Mounjaro or Wegovy?
From what we know, there’s not much difference. However, everybody is different, so some people may notice that side effects are worse on one or the other.
Is it safe to switch GLP-1 medications on my own?
No, it’s important to ensure you switch under medical supervision. They can ensure you’re starting on a dose that’s safe for you, and monitor your progress and any side effects you might experience.
