Switching from Mounjaro to Wegovy: All You Need to Know

By Irfan Mahmud, Pharmacist & Independent Prescriber

Key Takeaways

• In September 2025, the price of tirzepatide (Mounjaro) increased by 170% in the UK. It means that many patients are considering switching to semaglutide (Wegovy), a similar weight loss medication which is now considerably cheaper.

• Whilst switching from Mounjaro to Wegovy is possible, it may be necessary to take a 7-day break between medications. You may also need to start on the lowest dose of Wegovy before working your way back up to the strongest dose.

• Because there is no definitive clinical guidance on which strength dose of Wegovy you can switch to, you should always seek the advice of a medical professional before changing.

On 1st September 2025, the price of the weight loss injection Mounjaro increased by 170% in the UK. It could now cost upwards of £330 for a month’s supply of the strongest dose. Whether you’re a current Mounjaro patient or not, this news will understandably cause plenty of anxiety for plenty of people.

However, the similar weight loss injection Wegovy hasn’t been subject to the same price increases. At Cuva Health, the price of a month’s supply of Wegovy ranges from £129.50 for the lowest dose (0.25mg) to £239.90 for the strongest dose (2.4mg).

So what is Wegovy, how does it differ from Mounjaro, and is it safe to switch between them? Let’s take a look.

Mounjaro vs Wegovy: similarities and differences

DRUG: Mounjaro | Wegovy

AVG. WEIGHT LOSS*: 21% | 17%

MODE OF ACTION: GLP1 and GIP agonist | GLP1 agonist

STRENGTHS: SIX: 2.5mg, 5mg, 7.5mg, 10mg, 12.5mg, 15mg | FIVE: 0.25mg, 0.5mg, 1mg, 1.7mg, 2.4mg

PRICE RANGE: £130-£330 | £120-£250

DOSE: Once-Weekly Injection | Once-Weekly Injection

SIDE EFFECTS: common - nausea, vomiting, diarrhoea, constipation | common - nausea, vomiting, diarrhoea, constipation

The first thing to note about Wegovy is that it broadly works in the same way as Mounjaro: by suppressing your appetite and slowing the emptying of your stomach to reduce your calorie intake. The two medications are similar in a number of other ways:

• Both medications are once-weekly injections.

• One major clinical study into the effects of Wegovy also found it to be an effective treatment for obesity. On average, Wegovy users lose 17% of their starting body weight after 18 months of treatment.

• Wegovy and Mounjaro have similar possible side effects, the most common (affecting at least 1 in 10 people) including nausea, constipation, diarrhoea and vomiting.

• The eligibility requirements for Wegovy are the same as Mounjaro. Wegovy will only be prescribed to patients with a BMI of 30 or over, or patients with a BMI of at least 27 and who suffer from a weight-related condition.

However, there are also some key differences between Mounjaro and Wegovy to be aware of:

• Mounjaro works by mimicking the GIP and GLP-1 receptors in your brain, which are responsible for telling your body when it’s full. On the other hand, Wegovy only mimics the GLP-1 receptor.

• This difference in mechanism may explain why Wegovy users see slightly less weight loss on average than Mounjaro users. Whilst Wegovy users lose an average of 17% of their starting body weight over 18 months, Mounjaro users could lose 21% of their body weight in the same timeframe.

• Though it’s difficult to compare the doses of Wegovy and Mounjaro side-by-side, Mounjaro is generally considered to be a stronger medication because of its dual-action mechanism.

• Now, Mounjaro is also more expensive than Wegovy.

Because Wegovy is a similar medication to Mounjaro that’s also considered a safe and effective weight loss medication, it’s perhaps why so many patients are looking into switching. But is it possible?

Can you switch from Mounjaro to Wegovy?

Although in most cases it’s perfectly possible to switch from Mounjaro to Wegovy, you should always consult with a medical professional before changing. They’ll be able to examine your medical history, how you responded to weight loss medication in the past and assess your results so far to judge whether it’s safe for you to switch.

That being said, it’s certainly possible to switch from Mounjaro to Wegovy. But there are a few things you should consider before doing it.

How to switch from Mounjaro to Wegovy

If you are thinking of switching and your clinician has approved it, there are a few important things to bear in mind.

We would firstly recommend taking a break of around 7 days in between the two medications - which is when you would normally take your next dose of Mounjaro. That’s because it generally takes ~5 half-lives for a drug to achieve steady state, and ~5 half-lives for most of a drug to be eliminated from the body. Therefore, this break reduces the risk of the two medicines overlapping when switching. It’s best to speak with a clinician to get some personalised advice on how long your changeover period should be.

You should ideally start your Wegovy treatment on the lowest dose before working your way back up again. If you’re concerned about losing the effects of Mounjaro during this process then your clinician may consider switching you directly to a higher dose of Wegovy. They’re only likely to suggest this if you haven’t experienced any major side effects from the medication, however.

Although some studies have tried to compare the strength of Mounjaro and Wegovy, it’s difficult to do a direct comparison. However, this table should give you a reasonable idea of which doses it would be safe to switch to (in order to avoid any major side effects and maintain the benefits of the treatment you’ve had so far).

Mounjaro | Wegovy

2.5mg | 0.5mg or lower

5mg | 0.5mg or lower

7.5mg | 1mg or lower

10mg | 1.7mg or lower

12.5mg | 2.4mg or lower

15mg | 2.4mg or lower

Summary & Final Advice

Overall though, our first piece of advice still sticks: ask your clinician before switching from Mounjaro to Wegovy. Because whilst it is possible, it’s important to make sure you’re doing it safely.

Reviewed by Irfan Mahmud, Pharmacist & Independent Prescriber (GPhC Reg. No: 2080386)

Irfan is a UK-registered pharmacist and independent prescriber with expertise in weight management, primary care, and lifestyle medicine. As the founder of Cuva Health, he is dedicated to providing safe, clinically-approved treatments and clear, trustworthy health guidance.