Switching treatment
Switching from Mounjaro to Wegovy
Why people switch, what the process usually looks like, and how today's prices compare dose by dose.
Why the increase in price?
Eli Lilly, the manufacturer of Mounjaro, raised the UK list price from 1 September 2025 by up to 170%, with the 15mg dose rising from around £122 to £330 for a month's supply. The change brought UK pricing closer to other European markets. It doesn't affect NHS patients, but it does affect private prescriptions, which makes comparing prices and discounts more important than ever.
How do Mounjaro and Wegovy differ?
Both are weekly injections with strong results, but they work differently. Mounjaro (tirzepatide) acts on two hormones, GIP and GLP-1. Wegovy (semaglutide) acts on GLP-1 only. Because they're different medicines, your prescriber decides how to move between them.
Mounjaro
- Average weight reduction: up to 20%
- Active ingredient: tirzepatide
- Taken once a week
- Dose can go up, down or stay the same month to month
Today from £99.
Wegovy
- Average weight reduction: up to 17%
- Active ingredient: semaglutide
- Taken once a week
- Dose can go up, down or stay the same month to month
Today from £51.
How a switch usually works
Each pharmacy has its own process. This is the general shape of it.
Online consultation
Answer the new pharmacy's questions about your health, current treatment and progress so far.
Prescriber review
A prescriber reviews your history and decides which Wegovy dose to start you on. Some recommend an 'equivalent dose', others a full washout period first.
Timing your first dose
Your prescriber will tell you when to take your first Wegovy dose, usually in place of your next scheduled Mounjaro injection.
Review and adjust
Expect check-ins as you settle in. Tell your prescriber about any side effects.
Cheapest price by dose step
The lowest listed price for each step, today. Dose steps are not equivalent between the two medicines.
Who are Mounjaro and Wegovy for?
Both are usually approved for adults with a BMI of 30 or higher, or 27 or above with a weight-related condition. They're not suitable for everyone, including people with type 1 diabetes, inflammatory bowel disease, significant liver or kidney problems, or who are pregnant, breastfeeding or planning to conceive.
Do I have to start from 0.25mg Wegovy?
Not always. Many pharmacies use an 'equivalent dose' between Mounjaro and Wegovy, while others recommend a washout period between treatments. Review the advice carefully and ask your pharmacy's clinical team.