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How to Switch from Wegovy to Mounjaro (UK Guide)

This page is intended for informational purposes only and is aimed at individuals considering a switch from Wegovy to Mounjaro. It does not constitute medical advice or a recommendation to change treatments.

If you’re using Wegovy for weight loss but thinking about trying Mounjaro instead, you’re not alone. Many people in the UK are making the switch. Whether it’s due to side effects or because they’re not getting the results they hoped for, Mounjaro is now seen by many as the more effective option.

This guide will walk you through what switching involves, what to expect, and how to do it safely — all in simple terms.

Why switch from Wegovy to Mounjaro?

Wegovy and Mounjaro are both popular injections used to support weight loss. They work in similar ways by helping you feel fuller for longer and reducing appetite. But Mounjaro appears to go a step further.

While Wegovy contains semaglutide, Mounjaro contains tirzepatide, which works on two key hormones instead of just one. This dual action is believed to make Mounjaro more powerful when it comes to helping people lose weight.

A quick comparison:

  • People using Wegovy on average can lose up to 15% of their body weight over time.
  • With Mounjaro, that number on average can go up to 22.5% — based on studies at the highest doses.

Some people also switch because they find Mounjaro causes fewer side effects or feels gentler on the body.

Can I switch from Wegovy to Mounjaro?

If you’re currently taking Wegovy and meet the usual requirements for weight loss injections, you may be able to switch. It’s important to speak to a qualified healthcare professional before making any changes.

You may be eligible if:

  • You’re aged 18 or older
  • Your BMI is 30 or above, or 27+ with a weight-related condition like high blood pressure or sleep issues (With some providers you may be eligible under these BMI range down to lower 20’s – Please always check, a good place to start looking is here)
  • You’re not pregnant or breastfeeding
  • You’re not taking any medication that might clash with Mounjaro
  • You don’t have any health issues that make tirzepatide unsuitable

How do I switch from Wegovy to Mounjaro?

(PLEASE CONSULT A HEALTHCARE PROVIDER BEFORE MAKING ANY DECISIONS)

Here’s what a typical switch looks like:

  1. Stop taking Wegovy – You can either finish your current pen or stop immediately if advised to do so.
  2. Wait around 4 weeks – This allows time for semaglutide, the active ingredient in Wegovy, to leave your system. Some healthcare providers may recommend a shorter or longer gap depending on your individual circumstances.
  3. Start Mounjaro at the lowest dose – You’ll begin with 2.5mg, no matter what dose of Wegovy you were on.
  4. Follow a gradual increase plan – Your dose will go up slowly to help your body adjust and reduce side effects.

Important: Never change over to Mounjaro without speaking to your prescriber first. Starting it too soon after Wegovy can be risky. You’ll usually need to wait at least 4 to 5 weeks between the two treatments to allow your body to clear the previous medication. Overlapping them can increase the chance of side effects and may not be safe.

switch from wegovy to mounjaro

What should I expect when switching?

As Wegovy leaves your system, it’s common to notice a few temporary changes.

You might feel:

  • Hungrier than usual
  • A bit more tired
  • Slightly bloated or off-balance

This is normal and usually settles once Mounjaro starts working. The new medication will begin to take effect shortly after your first dose, helping to reduce appetite and support your weight loss journey.

Are there side effects with Mounjaro?

Like any medication, Mounjaro can cause side effects — though not everyone gets them. Most are mild and tend to ease over time.

Common side effects may include:

  • Feeling sick (nausea)
  • Tummy discomfort
  • Constipation or diarrhoea
  • A drop in energy levels
  • Changes in appetite

As your body adjusts, these usually fade. Most people find the side effects are manageable and improve as the dose increases gradually.

If you ever feel something isn’t right, speak to a healthcare provider.

Frequently asked questions

Can I switch straight to a high dose of Mounjaro?

No. Even if you were on a high dose of Wegovy, you must start Mounjaro at 2.5mg. They are different medications, and starting low helps prevent side effects.

Will I feel any withdrawal after stopping Wegovy?

Not in the usual sense. You might notice a return of appetite or some digestive changes, but these are temporary and not considered withdrawal symptoms.

Can I take Wegovy and Mounjaro at the same time?

No. You should never take them together or switch back and forth without medical supervision. Always wait the full 5 weeks before starting Mounjaro after stopping Wegovy.

Final thoughts

Switching from Wegovy to Mounjaro is a decision many are making, and for good reason. Mounjaro may offer better results and, for some, fewer side effects. Just be sure to do it the safe way, and always follow a healthcare professional’s advice.

⚠️ Disclaimer

Finally, this guide is for general information only and should not be taken as medical advice. Always speak to a qualified healthcare professional before making changes to your medication or treatment plan. Please see MHRA website for more in depth GLP-1 information.