Switching from Wegovy injections to Mounjaro injections: everything you need to know

Tuesday, July 21, 2026

If you’ve been using Wegovy injections for several months, it’s completely normal to start wondering whether Mounjaro might work better for you or vice versa.

Switching between these two weight management medications is possible and usually straightforward with the right guidance. This article explains why people switch, how the process works, and what you can expect along the way.

Start a weight loss consultation to check whether switching to Mounjaro is right for you.

In this article:

Why might you want to switch from Wegovy to Mounjaro?
How are Wegovy and Mounjaro different?
What are the results for weight loss on Mounjaro?
Is it safe to switch from Wegovy to Mounjaro?
How do you switch from Wegovy to Mounjaro?
Why do you need to start at the lowest dose again?
What can you expect in the first few weeks after switching?
When might it be better to stay on Wegovy for now?

Why might you want to switch from Wegovy to Mounjaro?

There are several reasons you might consider changing treatment after spending time on Wegovy:

You’ve reached a plateau. Some people continue losing weight steadily, but others notice progress slowing once on their maintenance dose and want to explore another option.
Your side effects haven’t fully settled. Symptoms like nausea or digestive discomfort often improve as your body adjusts to the medicine, but not always. Switching to a different injection could help as GLP-1 side effects can vary when comparing treatments.
You’re curious about what Mounjaro does in the body and how it's dual mechanism works. Both weight loss injections work through GLP-1 receptors, but Mounjaro also targets GIP receptors (1).
You’ve heard that Mounjaro leads to more weight loss. Clinical studies suggest Mounjaro may lead to a slightly higher average weight loss (2,3), though the weight loss difference between the highest dose of Wegovy and Mounjaro is very close. While individual responses vary, it’s normal to question whether switching could make a difference for you.
You’d like to try the newer treatment now available in the UK. Mounjaro was approved by the MHRA for weight management in the UK two years after Wegovy (4,5). Many people wonder whether the newer option might suit them more.

How are Wegovy and Mounjaro different?

Before switching treatments, it helps to understand Wegovy vs Mounjaro and compare the key differences. Although they are both once-weekly injections that reduce appetite, they contain different active ingredients and follow slightly different dosing pathways:

Feature	Wegovy	Mounjaro
Active ingredient	Semaglutide	Tirzepatide
How it works	Mimics GLP-1 hormone pathway	Mimics GLP-1 and GIP hormone pathways
Injection schedule	Once weekly	Once weekly
Dose range	0.25mg → 7.2mg	2.5mg → 15mg
Number of dose steps	6 strength levels	6 strength levels
Average weight loss	19-21% of starting body weight (6)	20-22.5% of starting body weight (7)
Manufacturer	Novo Nordisk	Eli Lilly
Licensed by MHRA	Approved in 2021 (4)	Approved in 2023 (5)
Available in the UK	Available in 2023 (8)	Available in 2024 (9)
Additional licensed health benefits	Wegovy is licensed to help lower the risk of serious heart problems, alongside diet and exercise, in adults who already have heart disease and who have a BMI of 27 or above (12)	Type 2 diabetes mellitus

What are the results for weight loss on Mounjaro?

This is one of the most common questions people ask when thinking about switching.

Direct comparison research found that people taking tirzepatide lost around 1% more weight on average than those taking semaglutide (2,3):

In the SURMOUNT-1 study, people taking the highest dose of Mounjaro (15mg) lost on average 20-22.5% of their starting body weight on average over 72 weeks (6).
In the STEP UP study, people taking the new highest dose of Wegovy (7.2mg) lost on average 19-21% of their starting body weight on average over 72 weeks (7).

That being said, many people are yet to reach the highest dose of Wegovy (7.2mg) and maintain a maintenance dose of 2.4mg. The result for 2.4mg of Wegovy in a clinical study was:

People taking 2.4mg lost an average of 15-17% of baseline body weight over 68 weeks (11).

Although these were separate studies with different participants and aren’t directly comparable, they prove that both treatments can produce substantial weight loss.

It’s also worth noting that figures from clinical trials are averages. Some people lose more weight on Wegovy, while others respond better to Mounjaro. There is no single “best” injection for weight loss. It’s about finding the medicine that you get along with better.

Is it safe to switch from Wegovy to Mounjaro?

Yes. Switching is generally considered safe, assuming you:

Do not take both medications at the same time. Because Wegovy and Mounjaro work on the same GLP-1 pathway, they should never overlap.
Leave at least 2 weeks between injections if no side effects and 4 weeks if suffered unmanageable side effects. For many people, this means starting Mounjaro on the same day as their usual injection schedule the following week.
Restart at the lowest dose. Everyone begins on a low 2.5mg starting dose of Mounjaro. This helps your body adjust safely to the new medicine.

How do you switch from Wegovy to Mounjaro?

The switching process is usually straightforward. You should:

Speak to your prescriber to confirm whether switching is appropriate based on your progress so far, current dose, and any side effects.
Take your final Wegovy injection as normal. Continue on your usual injection day rather than stopping treatment early.
Wait at least 2 weeks before starting Mounjaro.
Start Mounjaro at 2.5mg weekly. Even if you were using a higher Wegovy dose, treatment restarts at the lowest strength. This is an important safety step, not a setback.
Follow the usual dose increase schedule. Your dose of Mounjaro can increase gradually every 4 weeks if appropriate, until you reach a maintenance level that works well for you.

Your prescriber will guide you through each stage so the transition feels clear and manageable.

Why do you need to start at the lowest dose again?

Wegovy and Mounjaro are both weight loss injections, but they contain two different active ingredients: Semaglutide and Tirzepatide. This means that the dose isn’t transferable. You cannot "match" your current Wegovy dose with a higher starting dose of Mounjaro.

Starting at the lowest strength allows your body to adjust safely to the new medication and reduces the risk of side effects. Although it can feel like a step backwards at first, most people move steadily back up through the dose schedule over the following months.

What can you expect in the first few weeks after switching?

It’s extremely normal for the first month on a Mounjaro to feel a little different. Because you restart at the lowest dose, you may notice:

Appetite suppression feels weaker at first. The starting dose is designed to help your body adjust to the medication rather than provide the full treatment effect right away.
Side effects may briefly return. Mild digestive symptoms sometimes temporarily reappear during the early dose stages, even if they had settled on Wegovy. Find out more about Mounjaro side effects in our guide.
Weight loss may temporarily slow. Some people experience a plateau, or occasionally a small amount of regain, but this usually improves as doses increase.

This adjustment period is expected and doesn’t mean the medication isn’t working. For most people, the stronger appetite and weight effects develop gradually over the next 2 to 4 months as treatment reaches a maintenance dose.

When might it be better to stay on Wegovy for now?

Switching injections can help in the right situation, but it isn’t always necessary. It may be worth continuing with Wegovy if:

You have not yet increased the highest maintenance dose of 7.2mg
Your weight is still decreasing steadily
Side effects are mild and manageable

In these situations, adjusting your current plan may be enough to support further progress without changing medication.

It’s also worth noting that a single-dose Wegovy 7.2 mg pen was approved in the UK in 2026 for people whose weight loss has plateaued at the 2.4mg maintenance dose (10). This high dose isn’t suitable for everyone and you can decide what the right dose of Wegovy is right for you. For some people, increasing their dose may provide further progress without the need to switch.

If you’re thinking about changing treatments, a short online consultation with Oxford Online Pharmacy can confirm whether it’s appropriate and explain how to start your first Mounjaro dose safely.