Switching from Mounjaro to Wegovy: What you need to know

The latest price hikes for Mounjaro may have prompted you to consider switching to a different weight loss medication. But is there another good weight loss injection on the market that is cheaper than Mounjaro? Yes, there is, and it’s called Wegovy. Here’s what you need to know about switching from Mounjaro to Wegovy—covering the reasons, the process, what to expect, and how to make the transition as smooth as possible.

Five key takeaways

• You must take a one-week “washout” break between stopping Mounjaro and starting Wegovy.
• Your starting dose of Wegovy depends on your last Mounjaro dose—sometimes you can begin on a higher dose.
• Side effects may change (or even improve) after switching, but everyone’s experience is different.
• Price hikes and availability are driving many to consider switching.
• Support from a healthcare professional is key for a safe, successful transition.

Introduction: Why consider switching from Mounjaro to Wegovy?

Mounjaro and Wegovy are examples of popular weight loss injections prescribed for the treatment of obesity [1], [2].  

With recent massive price increases for Mounjaro, it’s no wonder people are looking for alternatives [3], [4][5][8]. Since the price of Wegovy, or semaglutide, has remained the same, switching from Mounjaro to Wegovy is a topic of interest for anyone on a weight loss journey.

If you’re weighing up your options, it’s important to understand the differences between these medications, how to make the switch safely, and what you can expect along the way [8], [9].

This guide covers everything you need to know about switching from Mounjaro to Wegovy, including practical advice, clinical insights, and tips for making your transition as smooth (and stress-free) as possible.

What are Mounjaro and Wegovy?

Both Mounjaro and Wegovy are injectable medications designed to help with weight loss, but they work in slightly different ways [6], [7].

• Mounjaro contains tirzepatide, a dual agonist that targets both GLP-1 and GIP receptors. This means it mimics two hormones involved in appetite regulation and insulin secretion, potentially leading to greater weight loss for some people [6],[8],[9].
• Wegovy contains semaglutide, a GLP-1 receptor agonist. It helps you feel fuller for longer and slows down stomach emptying, making it easier to eat less and lose weight [10][11].

Both are usually given as weekly injections and are part of a broader weight management plan that includes diet and exercise [2], [6], [7].

Why are people switching from Mounjaro to Wegovy?

There are a few reasons why someone might consider switching:

• Cost: Mounjaro’s price has recently increased by 170% in the UK, making it less accessible for many [4][5][12][13][14].
• Side effects: Some people find Mounjaro’s side effects hard to manage, while others may prefer the side effect profile of Wegovy [3][8][15][16].
• Effectiveness: While both are effective, individual responses vary. Some patients may find Wegovy works better for them—or fits their lifestyle more easily [8][9][10]. However, the results from studies suggest that Mounjaro is more effective at weight loss, producing an average of 22.5% weight loss compared to 12.7% for Wegovy[8].
• Availability: With demand for weight loss medications soaring, availability can sometimes be a deciding factor [4][5][12].

Whatever your reason, it’s important to make the switch safely and with the support of a healthcare professional.

How do Mounjaro and Wegovy work? The science in plain English

Let’s break it down:

• Mounjaro (tirzepatide): Works by mimicking two hormones—GLP-1 and GIP. These hormones help regulate appetite, blood sugar, and insulin. The dual action means you might feel fuller for longer and see greater weight loss, but also a higher chance of side effects [3], [8],[9].
• Wegovy (semaglutide): Mimics only GLP-1. It helps you feel full, slows how quickly food leaves your stomach, and lowers your appetite. It’s effective for many, with a slightly different side effect profile [10],[11], [19]

Both medications are most effective when combined with healthy eating, regular exercise, and ongoing support [2][6][7].

Is switching from Mounjaro to Wegovy safe?

Yes, switching can be safe—if done correctly. The key is taking a “washout” break: you’ll need to stop Mounjaro and wait one week before starting Wegovy. This gap helps reduce the risk of overlapping side effects and allows your body to adjust [3], [11].

Your healthcare provider will help you decide when and how to make the switch, taking into account your current dose, side effects, and weight loss progress.

How to switch from Mounjaro to Wegovy: Step-by-step

1. Finish your last dose of Mounjaro.
2. Wait one week (the “washout period”). This gives your body time to clear the medication and reduces the risk of side effects [3], [11].
3. Start Wegovy. Your starting dose will depend on your previous Mounjaro dose and your doctor’s advice [2][6][7].

Here’s a quick reference:

Last Mounjaro Dose	Starting Wegovy Dose
2.5 mg	0.25 mg
5 mg	0.5 mg
7.5 mg	1 mg
10 mg	1 mg
12.5mg	1.7mg
15mg	1.7mg

What side effects should you expect after switching?

Switching medications can mean a change in side effects. Some people find side effects like nausea or fatigue improve after switching to Wegovy, while others may experience new ones [3], [11], [19].

Common side effects for both medications include:

• Nausea
• Vomiting
• Diarrhoea or constipation
• Headache
• Fatigue

Most side effects are mild and improve over time. If you notice anything unusual or severe, contact your healthcare provider.

Practical tips for a smooth transition

• Plan ahead: Order your medication early so you can start straight away after the washout period.
• Track your symptoms: Keep a diary of how you feel before, during, and after the switch.
• Stay hydrated and eat light meals: This can help minimise nausea [20].
• Ask for support: Don’t hesitate to reach out to your pharmacy or contact us if you have questions or concerns.
• Keep up healthy habits: Weight loss medications work best when paired with good nutrition, regular exercise, and a positive mindset [20].

What if you don’t see results straight away?

It’s normal for weight loss to slow down or plateau, especially after changing medications. Don’t be discouraged—focus on building healthy routines, and remember that progress isn’t always linear [16], [20].

If you’re not seeing the results you want, your provider may adjust your dose or recommend additional support.

FAQs: Switching from Mounjaro to Wegovy

Who should consider switching from Mounjaro to Wegovy?

Anyone who’s struggling with side effects, facing cost issues, or looking for a different approach to weight management may want to explore switching. Always consult your healthcare provider first.

How do I know if Wegovy is right for me?

Your provider can help you decide based on your health history, weight loss goals, and how you responded to Mounjaro.

Can I switch back to Mounjaro later?

Yes, with medical supervision. Always follow your provider’s advice when making any medication changes.

Will I regain weight after switching?

Not necessarily. With the right support and healthy habits, most people maintain or continue their weight loss after switching .

Is there a risk of side effects getting worse?

Most people tolerate the switch well, but individual responses vary. Report any severe or persistent symptoms to your provider.

Who is this article for?

This guide is for anyone currently taking Mounjaro for weight loss, considering a switch to Wegovy, or supporting someone on this journey. Whether you’re a patient, carer, or healthcare professional, you’ll find practical advice, honest insights, and up-to-date references to help you make informed decisions.

This information is for general guidance only. For personalised medical advice, please consult your doctor or healthcare provider.

References

• 1] NHS (no date) Obesity. Available at: https://www.nhs.uk/conditions/obesity/ (Accessed: 5 September 2025).
• [2] NHS (no date) Obesity: Treatment. Available at: https://www.nhs.uk/conditions/obesity/treatment/ (Accessed: 5 September 2025).
• [3] Courier Pharmacy. (2025) Mounjaro side effects. Available at: https://courierpharmacy.co.uk/mounjaro-side-effects-2/ (Accessed: 27 August 2025).
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• [5] BMJ. (2025) Mounjaro: UK price rise for obesity drug sparks concern. Available at: https://www.bmj.com/content/390/bmj.r1776 (Accessed: 29 August 2025).
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• [7] electronic medicines compendium (emc) (no date) Summary of Product Characteristics: Wegovy 0.25 mg solution for injection in pre-filled pen. Available at: https://www.medicines.org.uk/emc/product/13799/smpc (Accessed: 5 September 2025).
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• [10] Medical Mojo. (2025) How does Wegovy work? Available at: https://medicalmojo.co.uk/how-does-Wegovy-work/ (Accessed: 27 August 2025).
• [11] Medical Mojo. (2025) Wegovy side effects: what are they? Available at: https://medicalmojo.co.uk/Wegovy-side-effects-what-are-they/ (Accessed: 27 August 2025).
• [12] ITV News. (2025) Mounjaro manufacturer admits pressure from Trump contributed to price hike. Available at: https://www.itv.com/news/2025-08-28/mounjaro-manufacturer-admits-pressure-from-trump-contributed-to-price-hike (Accessed: 29 August 2025).
• [13] Reuters. (2025) Trump calls out weight-loss drugs in target price cut push. Available at: https://www.reuters.com/business/healthcare-pharmaceuticals/trump-calls-out-weight-loss-drugs-target-price-cut-push-2025-05-12/ (Accessed: 29 August 2025).
• [14] BBC News. (2025) Mounjaro weight loss drug price to rise sharply in the UK. Available at: https://www.bbc.co.uk/news/articles/cvg3ykg4jrro (Accessed: 29 August 2025).
• [15] Courier Pharmacy. (2025) Can you drink alcohol while taking Mounjaro? Available at: https://courierpharmacy.co.uk/can-you-drink-alcohol-while-taking-mounjaro-2/#h-how-does-mounjaro-cause-weight-loss (Accessed: 27 August 2025).
• [16] Courier Pharmacy. (2025) Why am I not losing weight on Mounjaro? Available at: https://courierpharmacy.co.uk/why-am-i-not-losing-weight-on-mounjaro/ (Accessed: 27 August 2025).
• [17] Courier Pharmacy. (2025) Mounjaro side effects. Available at: https://courierpharmacy.co.uk/mounjaro-side-effects-2/ (Accessed: 27 August 2025).
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• [20] Courier Pharmacy. (2025) The ultimate Mounjaro diet guide. Available at: https://courierpharmacy.co.uk/the-ultimate-mounjaro-diet-guide/ (Accessed: 5 September 2025).