Switching from Mounjaro to Wegovy: How it Works

Weight loss injections, such as Mounjaro and Wegovy, have become increasingly popular in the UK, especially among people who have struggled to shed the pounds through diet and exercise alone. While both can yield significant results, Mounjaro is considered the more effective option.

That being said, Mounjaro doesn’t work for everyone. Everyone’s journey is unique, so you may find that you start using the treatment and discover that it isn’t having the intended impact. You may not be able to tolerate the side effects, might not be losing much weight, or could potentially be concerned about the increasing cost of treatment. If any of these ring true to you, a potential solution lies with changing your medication, with Wegovy being the most likely alternative.

In this article, we’ll discuss the process of switching from Mounjaro to Wegovy, so you can have a clear understanding of what to expect and be able to make an informed decision. Let’s get started. 

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What is the Difference Between Mounjaro and Wegovy?

Mounjaro (tirzepatide) and Wegovy (semaglutide) are both approved weight loss injections in the UK and are glucagon-like peptide-1 (GLP-1) receptor agonists. This means they bind to the GLP-1 receptors in your body to suppress your appetite, limit food cravings, and promote weight loss.

However, Mounjaro is known as a dual-agonist, as it also binds to the glucose-dependent insulinotropic polypeptide (GIP) receptors, which can enhance the weight loss effects and regulate insulin secretion and blood sugar levels. The fact that Mounjaro targets both receptors and Wegovy works on just one means the former is viewed to be most effective when it comes to weight loss.

Results seem to back up this notion, with Mounjaro achieving an average weight loss of 22.5% at the highest dose after 72 weeks. Wegovy, meanwhile, can lead to a 15% weight reduction at the maximum maintenance dose after 68 weeks.

While both treatments are subcutaneously injected once per week, Mounjaro’s dosing schedule titrates higher than Wegovy’s, further enhancing its efficacy. You can find out more information about the two dosage regimens and other comparisons in our Mounjaro vs Wegovy guide. 

Can I Switch from Mounjaro to Wegovy?

Yes, you can switch from Mounjaro to Wegovy, but it isn’t a decision you should make alone. The matter should instead be discussed first with a medical professional, such as a licensed clinician. This is to ensure that your potential new treatment is suitable for your circumstances.

Before switching from Mounjaro to Wegovy, or any other weight loss medication, the clinician will need to review a few items. These include:

• Your current progress with Mounjaro
• Any side effects you have experienced
• Other health conditions you have or medications you take
• Your weight loss goals

Because both injections change how your body regulates its appetite and blood sugar levels, switching without medical guidance could increase the likelihood of side effects or lower the effectiveness. It’s always better to be safe than sorry. 

Why Consider Switching from Mounjaro to Wegovy?

There are several reasons why you might want to switch from Mounjaro to Wegovy, including side effects, effectiveness, availability, and cost. Careful consideration of all these points is crucial to ensuring you make an informed decision about which is the right weight loss injection for you.

Here are the most common reasons for moving from Mounjaro to Wegovy in more detail: 

Mounjaro Price Increase 2025

Currently, the most pressing reason for switching from Mounjaro to Wegovy is the cost. From September 2025, the price of Mounjaro could rise by up to 170% in the UK, putting financial pressure on people paying for private prescriptions or limiting its availability. Wegovy, on the other hand, is not affected by the price rise, so it is likely to be a more affordable long-term option for many people. 

Side Effects

Although both treatments can cause side effects, such as nausea, diarrhoea, and constipation, some people find that they can tolerate Wegovy better than Mounjaro (and vice versa). If you’ve struggled to manage Mounjaro side effects, your clinician may recommend trying Wegovy to see if your body finds it more tolerable. 

Effectiveness

Despite Mounjaro showing strong results in clinical trials, Wegovy is also a successful option, with well-documented evidence demonstrating its effectiveness. If your weight loss has plateaued on Mounjaro, or your clinician believes Wegovy may be a more effective option, you might consider switching. 

Availability

Sometimes, supply issues can affect one medication more than another. With the recent Mounjaro price increases being announced by its manufacturer, there is the potential that it may be more difficult to obtain privately than Wegovy in the future.

Additional Health Benefits

Wegovy is currently the only weight loss medication that is licensed to reduce the risk of cardiovascular issues in people with heart problems and obesity. Although clinical trials have shown that Mounjaro can offer similar benefits, the treatment is not currently licensed for this purpose in the UK. 

Impact on Birth Control

According to the Faculty of Sexual & Reproductive Healthcare (FSRH), there is no evidence that semaglutide (Wegovy) reduces the effectiveness of oral contraceptives such as the combined pill or ‘mini pill’. However, it recommends that people using Mounjaro use a barrier method of contraception (such as condoms) in addition to the pill for the first four weeks of treatment, plus for four weeks after any dose increase. 

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What to Think About When Moving From Mounjaro to Wegovy

When you change from Mounjaro to Wegovy, it isn’t simply about swapping one injection for another. There are several important considerations, including how the dosages differ, whether the side effects may feel different, and what results you can realistically expect. Thinking about these factors before switching can help you feel better prepared and more confident.

Some of the things to think about include:

• Dosages: Mounjaro and Wegovy have different starting doses and escalation schedules, which means you cannot simply swap straight from one to the other.
• Effectiveness: Some people may respond better to Mounjaro, while others will tolerate Wegovy well. One study comparing the two injections found that after one year, the average weight loss with tirzepatide (Mounjaro) was 15.3% compared to 8.3% with semaglutide (Wegovy). However, everyone’s weight loss journey is unique to them, so how much weight you can lose will depend on how well your body responds to the medication, as well as other factors like the lifestyle changes you make. 
• Side Effects: Even if you have tolerated Mounjaro well, you may experience Wegovy side effects when you start treatment or increase (titrate) your dose. That’s because they contain different active ingredients, so it is important to monitor your response to help you and your clinician manage them appropriately.
• Support: Both weight loss injections work best alongside a diet plan and exercise programme, and switching is not a replacement for lifestyle changes. If you’ve been following our Mounjaro and exercise guide, most of these tips can be transferred to Wegovy once you’ve switched, helping to make the change from Mounjaro to Wegovy as seamless as possible.
• Priming the Pen: Wegovy pens don’t need priming before every dose, only for your first injection. This is different to Mounjaro, which requires priming before each and every usage. You can find more information about how to use Wegovy in our dedicated guide. 
• Storage: Although both treatments should be refrigerated before opening, they can be kept at room temperature (up to 30°C) after the first use. The difference is that Wegovy can only be left out for 28 days, while Mounjaro lasts for 30 days.

If you have any other queries about switching from Mounjaro to Wegovy or what to expect, our specialist clinicians are here to help. 

How to Change from Mounjaro to Wegovy

Switching from Mounjaro usually involves a structured process to keep you safe, reduce the chance of unwanted side effects, and help you gradually implement lifestyle changes. This consists of an initial assessment, a ‘washout’ period between your last dose of Mounjaro and first dose of Wegovy, followed by regular monitoring to ensure your new treatment is working as intended.

Let’s take a look at the steps you’ll need to take when moving from Mounjaro to Wegovy in more detail:

• Assessment: Complete a Wegovy consultation with our clinician, stating that you wish to change from Mounjaro to Wegovy and provide any relevant information, such as current weight loss, side effects, and medical history. 
• Washout Period: Most people will need to leave a short gap between their last Mounjaro injection and the first Wegovy one. This is usually one week, but it may be more. Our clinician will advise you on the appropriate interval between treatments.
• Starting Dose: Our clinicians will help you determine the best starting dose of Wegovy. This will depend on a number of factors, including your current Mounjaro dosage, the results you’ve had so far, and how well you have tolerated the medication. 
• Monitoring and Long-Term Plan: Your clinician will monitor your progress and any side effects at regular intervals. They will also provide ongoing advice to help you maintain your achievements once you reach your maintenance dose.

Switching from Mounjaro to Wegovy Dosage Schedules 

Both Mounjaro and Wegovy are injected once per week, ideally on the same day and time. Mounjaro, however, is available in six different doses, while Wegovy has only five. This means you will arrive at your highest maintenance dose of Wegovy than you would with Mounjaro.

Mounjaro starts at a 2.5 mg weekly dose and increases every four weeks up to a maximum of 15 mg, a process that lasts for up to 21 weeks. More information on this can be found in our ‘Mounjaro Dosage for Weight Loss’ guide. 
 

Wegovy, on the other hand, starts at 0.25 mg per week and increases every 4 weeks until you reach the maintenance dose of 2.4 mg or one that you feel comfortable with. This process usually lasts for up to 17 weeks. If you’d like more information about Wegovy’s dosage schedule, please read our dedicated article. 

Remember that not everyone’s journey is the same. As a result, you may find that it takes a bit longer to reach the highest maintenance dose, or you could even decide to remain on a lower dose if you’re achieving an adequate level of weight loss. Our clinicians will be able to help you decide what is best for your circumstances. 

Switching from Mounjaro to Wegovy: Frequently Asked Questions

Making the change from Mounjaro to Wegovy is a big step and can raise many questions. Being curious or apprehensive is natural, so here, we answer some of the most common queries about switching, including whether you’ll need to restart on the lowest dose, if side effects will change, and whether there are other options available.

Can I Take Mounjaro and Wegovy Together?

No, you should never take Mounjaro and Wegovy together. This is because both medications work in similar ways, and taking them at the same time can increase the risk of side effects without enhancing the results. If you’re unsure about which treatment is best for you, it’s important to consult a healthcare professional.

Even if you think your progress is slow, combining them is unsafe. Instead, speak to your clinician about whether increasing your dose or considering an alternative is appropriate. 

Will I Get Withdrawal Symptoms if I Change from Mounjaro to Wegovy?

No, there are no withdrawal symptoms when you switch from Mounjaro to Wegovy. However, you may notice that your appetite returns when you stop your medication or during your washout period. Sticking to your diet and exercise plan will help you continue with your weight loss progress.

If you experience any new side effects when you change weight loss medications and you are concerned, contact your clinician for more advice.

Will I Need to Begin on the Starting Dose of Wegovy?

Although it’s generally advised to begin on the lowest dose of Wegovy when switching from Mounjaro, this may not necessarily need to be the case. Instead, our clinicians will determine the most suitable starting point for you, based on a number of factors.

Potential considerations include your current dosage of Mounjaro, results achieved thus far, and how you are coping with the side effects. 

Wegovy

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• Approved Weight Loss treatment
• Weekly injection
• Reduces risk of heart attack & stroke

• Discreet delivery next working day
• Online prescription - No doctor visit

Prices from £139.99 Review More Prices

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Is Mounjaro Stronger than Wegovy?

Although Mounjaro can produce greater average weight loss results because it binds to the receptors of two different digestive hormones, it does not mean Wegovy is not effective. Many patients achieve significant, sustainable weight loss with Wegovy, especially when they are supported with diet and lifestyle changes.

It is difficult to directly compare Mounjaro and Wegovy because they work in slightly different ways, contain different active ingredients, and are administered in different doses. 

Is it Easy to Move from Mounjaro to Wegovy?

Yes, it is relatively straightforward to switch from Mounjaro to Wegovy if you follow the instructions of your clinician. They will guide you through stopping Mounjaro, starting Wegovy, and monitoring your response and progress. Most people can transition between the medications pretty quickly with little disruption to their treatment plan.

You’ll usually need to have a short break between your last Mounjaro injection and your first Wegovy injection, just to make sure the active ingredients do not interact. Our ‘How to inject Wegovy safely step by step guide’ has everything you need to know about taking semaglutide properly.

Can I Switch Back from Wegovy to Mounjaro?

Yes, it is possible to switch from Wegovy back to Mounjaro if you find your new treatment isn’t working as planned. However, this can only be done if your clinician advises that it’s safe for you to do so and is the right move for your overall health. 

Are There Other Weight Loss Treatments Available?

Yes, Mounjaro and Wegovy are not the only weight loss treatments available. Generic liraglutide or Nevolat is another type of weight loss injection that contains the active ingredient liraglutide and is taken once daily rather than weekly.

If you are not sure about injecting yourself with medication, several weight loss pills are available, including:

• Xenical: Contains 120 mg of the active ingredient orlistat and works by blocking the absorption of fat from your diet. Clinical trials show that 37% of people taking orlistat lost at least 5% of their starting body weight after 2 years, compared to 19% given a placebo.
• Alli: An over-the-counter version of orlistat, but it contains a lower 60 mg dose that does not require a prescription. However, you will still need a short consultation with a clinician so they can check it is safe for you to take.
• Mysimba: A prescription-only weight loss pill that contains two active ingredients, bupropion and naltrexone. It works by suppressing your appetite and blocking the brain's reward response to food. The average weight loss with Mysimba after 56 weeks is 8.1%.

Our dedicated weight loss page has all the treatments we can provide and a wealth of information to help you make an informed choice.

Choosing The Right Support for Your Weight Loss Journey for a Smooth Transition

Switching from Mounjaro to Wegovy can feel daunting, but with the right support, it can be a safe and effective change. Whether you’re motivated by side effects, availability, or the upcoming Mounjaro price hikes, Wegovy is an effective alternative that continues to help thousands of people reach their weight loss goals with real results.

At Prescription Doctor, our weight loss service makes the process as simple and supportive as possible. From convenient online consultations to discreet delivery and ongoing clinical support, including diet plans, side effects management advice, and tips for getting the most out of Wegovy, we’re here to help you take the next step with confidence.

Ready to make the change? Begin your Wegovy consultation today. 

Authored By

Leanne Edermaniger

Medical Content Writer

Leanne is a science and health content writer focusing on human health and biology while utilising her solid academic background.

Published on: 19/08/2025

Reviewed By

Mohamed Imran Lakhi

MPharm - Lead Pharmacist

Imran Lakhi is the superintendent pharmacist and founder at Prescription Doctor. He has been at the core of our team.

Reviewed on: 19/08/2025