Switching From Mounjaro to Wegovy: What You Need to Know

Mounjaro is an effective weight loss treatment – but it’s not right for everyone. Mounjaro price increases have left some patients concerned about the cost of the treatment. Others find the medication just doesn’t agree with them.

So, if you’re on Mounjaro, you might be thinking about switching to Wegovy, another GLP-1 weight loss medication used for weight management. But how can you do this safely?

Here, we explain what the process involves, with the help of our Lead Pharmacist Aamina Rafiq.

The Difference Between Mounjaro and Wegovy

Wegovy and Mounjaro are both weekly injections that work in similar ways. The active ingredient in Wegovy is semaglutide. However, Mounjaro contains tirzepatide.

Both medications are glucagon-like peptide-1 (GLP-1) receptor agonists. They mimic the hormone GLP-1, which sends messages to your brain to let you know you are full. They also slow down the rate food leaves your stomach. So you feel fuller quicker – and for longer.

However, Mounjaro is a dual agonist. This means it targets two hormones: GLP-1 and glucose-dependent insulinotropic polypeptide (GIP).

Because Mounjaro is a dual agonist that also mimics GIP, some clinicians suspect that’s why it can have a stronger effect. In clinical trials, patients lost an average of 22.5% of their body weight after 72 weeks on Mounjaro. On Wegovy, patients lost an average of 16.9% after 68 weeks.

The cost of Mounjaro is typically higher than Wegovy. Its manufacturer, Eli Lilly, increased its wholesale price in the UK on 1 September, 2025. This meant every private provider in the UK had to raise their Mounjaro prices.

Our Wegovy vs Mounjaro article explains the differences between the two medications.

Can You Start Wegovy After Mounjaro?

Yes. You can start Wegovy after Mounjaro. But how long do you need to wait?

You’ll just need to take a short, one-week break (called a “washout period”) after stopping Mounjaro, before you can start using Wegovy.

“This short pause is a really important step to make sure the switch is safe and your body has time to adjust,” explains Aamina Rafiq, Lead Pharmacist at Simple.

How to Switch From Mounjaro to Wegovy Safely

Switching from Mounjaro to Wegovy is straightforward. To switch with Simple, you’ll just need to fill in an assessment form for Wegovy. This will ask you what dose of Mounjaro you’re using. We’ll then help you find the most appropriate dose.

You need to take a short, one-week break before you start using Wegovy. So if you take your last dose of Mounjaro on a Monday, you can start Wegovy the following Monday. This advice is the same no matter what dosage of Mounjaro you’re currently taking. This short pause is necessary to reduce the risk of side effects.

“The reason we ask patients to take this break is to keep you safe,” says Aamina.

“If you overlap two GLP‑1 medications, your body ends up adjusting to both at the same time. That can increase the risk of unpleasant side effects like nausea or vomiting. And in some cases, more serious complications.”

Can I Switch to a Higher Dose of Wegovy Straight Away?

Yes. When you switch from Mounjaro, you don’t necessarily have to start Wegovy on the lowest dose. Instead, you may be able to start on a higher dose of Wegovy straight away.

Our clinical team will help you find the Wegovy dose that best suits you. We’ll base this on your current Mounjaro dosage, how well you tolerate the medication and your results so far.

The Wegovy vs Mounjaro doses table below shows the recommended Wegovy dose, based on your current Mounjaro dose. You can also choose to start on a lower dose of the medication.

Current Mounjaro Dose	Recommended Wegovy Dose
2.5 mg	0.5mg	Low Dose
5 mg	1mg	Medium Dose
7.5 mg	1.7mg	High Dose
10 mg	2.4mg	High Dose
12.5 mg	2.4mg	High Dose
15 mg	2.4mg	High Dose

What Side Effects to Expect After Switching

Many patients worry about side effects when switching from Mounjaro to Wegovy. But the side effects of Wegovy are very similar to the side effects of Mounjaro. The most common ones are stomach-related (nausea, diarrhoea, constipation).

You might notice that side effects, like nausea and fatigue, get better when you switch to Wegovy. But every person responds to the treatment differently.

Some people notice changes in side effects when they increase their dose or when they adjust their dosing schedule.

Will Switching Affect My Weight Loss Progress?

How much Wegovy will suppress your appetite will depend on which dose you switch to. However it is important to note that not everyone will experience the same level of appetite suppression. Every patient’s journey is unique.

We have recommended Wegovy doses for each Mounjaro dose. So, if you’re on a higher dose of Mounjaro, you don’t have to start from the lowest dose of Wegovy. This can help you continue your weight loss progress with less interruption.

However, the right dose will be the one where you’re seeing results, while keeping side effects to a minimum. Your prescriber will help you choose the safest, most effective option.

“If you’re concerned about your weight loss progress, it’s worth remembering weight care isn’t always a straight line,” says Aamina.

“Small changes or plateaus are completely normal. What matters is that you keep building healthy routines with your food, movement, and daily habits, while letting the medication support you along the way.”

Speak to a Healthcare Professional

You’re not alone in making your decision. And no matter what medication you decide to use, we can support you throughout your journey. Our clinical team can help tailor your dosing schedule and support long-term weight management. If you need guidance, call our team on 0141 774 5023 or contact us here.

“Our role is to make this process as simple as possible for you,” says Aamina. “When you switch with us, you’ll receive guidance from our clinical team, reminders when it’s time to reorder, and access to resources designed to help you stay on track.

“We also know medication is only one part of the picture. That’s why we provide advice articles on nutrition, exercise, and building the mindset that supports lasting results. Patients who combine medication with these lifestyle habits often feel more confident and in control of their journey.”

You can visit our online doctor weight loss clinic to see what weight loss options are available to you.

Key Takeaways

• How to Switch: Simply fill in an assessment form and tell us what Mounjaro dose you’re using. We can recommend a suitable Wegovy dose.
• Take a One-Week Break Between Treatments: Patients must have a one-week “washout period”. This means taking a break between stopping Mounjaro and starting Wegovy.
• You Can Switch to a Higher Dose: If you’re on a higher dose of Mounjaro, you can switch to a suitable higher dose of Wegovy straight away. This can help you keep momentum. We’ll help you find the most suitable dose.
• Side Effects of Wegovy and Mounjaro are Similar. If you’re worried about side effects, you don’t have to switch to a higher dose of Wegovy. You can start on the lowest Wegovy dosage and increase gradually.
• Get Support From Your Provider: This will keep you safe and provide you with peace of mind.

References

Wilding, J.P.H., Batterham, R.L. and Calanna, S. (2021). Once-Weekly Semaglutide in Adults with Overweight or Obesity. The New England Journal of Medicine, [online] 384(11), pp.989–1002. doi: https://doi.org/10.1056/NEJMoa2032183.

Jastreboff, A.M., Aronne, L.J., Ahmad, N.N., Wharton, S., Connery, L., Alves, B., Kiyosue, A., Zhang, S., Liu, B., Bunck, M.C. and Stefanski, A. (2022). Tirzepatide Once Weekly for the Treatment of Obesity. New England Journal of Medicine, [online] 387(3), pp.205–216. doi: https://doi.org/10.1056/nejmoa2206038.

Fick, M. (2025) Eli Lilly to hike UK price of Mounjaro weight-loss, diabetes medicines by 170%, Reuters. Available at: https://www.reuters.com/business/healthcare-pharmaceuticals/eli-lilly-hike-uk-price-mounjaro-weight-loss-diabetes-medicines-by-170-2025-08-14/ [Accessed: 14 August 2025]

Authorship

Editor’s note: This article was originally published on 14 August, 2025 . It has been updated for accuracy, readability and completeness.