If you are currently taking Mounjaro (tirzepatide) and considering a change to Wegovy (semaglutide), you may be wondering how the switch works, whether it is safe, and what differences to expect. With recent price changes to Mounjaro and increasing availability of Wegovy, many patients are exploring this transition. This guide explains why patients are making the switch, the safety considerations, how the medications differ in dosing and effectiveness, and what steps to follow for a smooth transition.

Why Patients Are Switching from Mounjaro to Wegovy

An increasing number of patients in the UK are moving from Mounjaro (tirzepatide) to Wegovy (semaglutide), and the reasons are both practical and clinical. From September 2025, Eli Lilly, the manufacturer of Mounjaro, will raise the UK list price to align with international markets. This means patients nationwide will see higher treatment costs across pharmacies, clinics, and digital providers.

For many patients, this price shift is the main driver behind switching.

Cost aside, some patients also find Wegovy easier to tolerate. While side effects between the two medications are broadly similar, certain individuals experience fewer or milder effects on Wegovy compared with Mounjaro.

Here are the main reasons patients are choosing to switch:

• Rising costs of Mounjaro as the manufacturer increases UK pricing.

• Side effect tolerability, with some patients finding Wegovy more manageable.

Ultimately, deciding between the two treatments depends on your health needs, preferences, and affordability. Consulting a healthcare provider is essential to determine whether switching to Wegovy is the right option for you.

Is It Safe to Move from Mounjaro to Wegovy?

Yes — in most cases, switching from Mounjaro (tirzepatide) to Wegovy (semaglutide) is considered safe. Both treatments belong to the GLP-1 class of medications, which work in similar ways to support weight loss. However, they are not interchangeable, meaning you cannot use them at the same time or swap doses directly.

When moving from Mounjaro to Wegovy, it’s normal to have a short break between treatments. A short transition period is typically required to allow the previous medication to leave your system before beginning the new one. During this time, most people do not experience withdrawal symptoms, though some may notice mild changes such as temporary increases in appetite.

It’s important to remember that everyone responds differently to treatment. While some people may find Wegovy easier to tolerate, others may not notice a significant difference in side effects. Common effects — such as nausea, constipation, or indigestion — can occur with either medication, though they are usually mild and improve with time.

Before making the switch, you should always consult with a healthcare professional. They will review your medical history, current dosage, and treatment goals to decide on the safest and most effective way to transition. This ensures that your progress is maintained while minimising any risks.

Mounjaro vs Wegovy: Key Differences in Dosing and Effectiveness

Both Mounjaro (tirzepatide) and Wegovy (semaglutide) are GLP-1 based treatments designed to support weight loss, but there are important differences between them that patients should understand.

Dosing Schedules

Although both medications are taken as weekly injections, they follow different dose escalation schedules:

• Mounjaro begins at 2.5mg weekly, with gradual increases up to a maximum of 15mg. Not all patients tolerate the higher doses well, and side effects may become more noticeable at stronger levels.

• Wegovy starts at 0.25mg weekly and typically increases every 4 weeks, with a maximum licensed dose of 2.4mg. Patients may remain on a lower dose if it is effective and well tolerated.

Because the dosing regimens are different, the two medications are not interchangeable. Switching requires clinical oversight to ensure the right starting point and safe escalation.

Effectiveness

Both Mounjaro and Wegovy are considered highly effective weight loss treatments, but they act slightly differently:

• Wegovy works by mimicking the GLP-1 hormone, which reduces appetite, slows digestion, and helps regulate hunger.

• Mounjaro targets both GLP-1 and GIP receptors, using two hormones to influence blood sugar and appetite regulation.

Clinical trial results show that both treatments can deliver significant weight loss outcomes. Patients on the highest doses of Wegovy lost up to 20.7% of their body weight, while those on the highest doses of Mounjaro lost up to 20.9%. These results suggest both medications can be highly effective when used consistently alongside lifestyle changes.

Side Effects

The most common side effects of both medications are gastrointestinal, including nausea, constipation, diarrhoea, and indigestion. While tolerability can vary, some patients report differences in how long side effects last or how intense they feel. As with any medication, individual experiences differ, and it is important to work with a healthcare provider to manage symptoms and adjust treatment where necessary.

In summary, both Mounjaro and Wegovy provide effective weight loss support with different dosing approaches and mechanisms of action. Which one is best suited depends on your medical history, response to treatment, and long-term goals.

Starting Wegovy After Mounjaro: Can You Continue at a Higher Dose?

One of the main concerns when switching from Mounjaro (tirzepatide) to Wegovy (semaglutide) is whether you need to start at the lowest dose again. In many cases, the answer is no.

If you have recently been using Mounjaro, your healthcare provider may allow you to begin Wegovy at a higher dose that reflects your current treatment progress and tolerance. This approach helps you avoid restarting from the lowest dose, which could otherwise cause unnecessary delays, loss of momentum, or additional side effects during re-escalation.

Starting at a higher dose is not suitable for everyone, but it may be recommended when:

• You have been on Mounjaro long enough to build up tolerance to GLP-1 medication.

• Your weight loss has been stable or progressing at your current dose.

• You have not experienced severe side effects that would make a higher starting dose unsafe.

Even when continuing at a higher dose, close clinical monitoring is important. Your prescriber will review your medical history and treatment experience to determine the safest entry point and may adjust your Wegovy dose if side effects occur.

In summary, switching from Mounjaro to Wegovy does not always mean starting over at the lowest strength. With medical guidance, many patients can continue at an equivalent higher dose to maintain progress and minimise treatment interruptions.

Step-by-Step Guide to Making the Switch

Switching from Mounjaro (tirzepatide) to Wegovy (semaglutide) can be straightforward when done under medical guidance. Here’s what the process typically looks like:

1. Consult your healthcare provider: Before making any changes, your prescriber will review your medical history, current dose, and treatment response to ensure a safe transition.

2. Stop Mounjaro: After taking your final Mounjaro injection, you will need to pause treatment. A short break is required to allow the medication to leave your system.

3. Wait the recommended period: Most patients wait around 7 days before starting Wegovy. This gap helps prevent overlapping medication effects while keeping treatment interruptions minimal.

4. Start Wegovy at the advised dose: Your prescriber will determine the safest starting point. In some cases, patients can begin on a higher dose of Wegovy if they have already built tolerance with Mounjaro, avoiding the need to restart from the lowest dose.

5. Maintain a consistent dosing schedule: Once you start Wegovy, choose a fixed day of the week for your injections and stick to it for steady treatment.

6. Monitor and adjust if needed: Regular check-ins with your prescriber help manage side effects, adjust dosing, and ensure your weight loss progress continues smoothly.

By following these steps with clinical oversight, patients can move from Mounjaro to Wegovy safely and effectively, minimising disruption and maintaining momentum in their weight loss journey.

Will You Experience Withdrawal Symptoms When Switching From Mounjaro to Wegovy?

Most patients do not experience withdrawal symptoms when transitioning from Mounjaro (tirzepatide) to Wegovy (semaglutide). Because both are GLP-1 based medications, the effects on appetite and hunger regulation usually continue during the short break between treatments. Some people may notice a temporary increase in appetite, but this is generally mild and manageable.

If you are using Mounjaro for diabetes management rather than weight loss, the situation is different, and changes to your medication must only be made under strict medical supervision. For weight loss use, maintaining healthy eating and lifestyle habits during the transition helps minimise any impact.

Always inform your healthcare provider if you experience unexpected or severe changes during the switch.

Frequently Asked Questions