Updated November 2026 · Based on the SURMOUNT-4 and STEP 1 trials and NICE guidance
The short version: when people stop Mounjaro or Wegovy, most of them regain weight. In the trials, people who stopped regained roughly half to two-thirds of the weight they'd lost within a year, and improvements in blood pressure and blood sugar faded too. That doesn't mean the medicine failed. It means obesity is a long-term condition, and it pays to plan how you'll stop, or whether you'll stay on a maintenance dose, before you start.
What happens when you stop Mounjaro?
The SURMOUNT-4 trial tested this directly. Everyone took Mounjaro for 36 weeks and lost an average of 20.9% of their body weight. Then half switched, without knowing it, to a placebo, while the other half carried on.
Over the next 52 weeks:
| Kept taking Mounjaro | Switched to placebo | |
|---|---|---|
| Weight change after the switch | lost a further 5.5% | regained 14.0% |
| Total change from the start of the trial | down 25.3% | down 9.9% |
| Kept at least 80% of the weight they'd lost | 89.5% | 16.6% |
So people who stopped kept off some of their weight, but most regained a large part of it within a year.
What happens when you stop Wegovy?
The STEP 1 trial followed people for a year after they stopped Wegovy (semaglutide 2.4mg). They'd lost an average of 17.3% of their weight over 68 weeks. A year after stopping, they had regained about two-thirds of it (11.6 percentage points), leaving them a net 5.6% below their starting weight.
The health benefits, such as lower blood pressure, blood sugar and cholesterol, mostly went back towards where they started too.
Why does the weight come back?
These medicines work by acting on appetite hormones: you feel less hungry and fuller sooner. When you stop, those signals return to how they were. At the same time, your body tends to defend a higher weight after weight loss, by increasing hunger and slightly lowering the energy you burn. That combination makes regain likely unless something else changes.
How to lower the risk of regain
There's no proven way to stop and keep all the weight off, but these steps can help. Discuss them with your prescriber.
1. Make the decision with your prescriber, not on impulse Don't stop suddenly because of cost or a missed delivery without a plan. Your prescriber can talk you through your options.
2. Ask about stepping down rather than stopping There's no official UK tapering schedule, but some prescribers reduce the dose gradually or move people to a lower maintenance dose. A lower dose can also be cheaper. This is a clinical decision, so don't change your dose on your own.
3. Build habits while you're still on treatment The months on medication, when your appetite is quieter, are the best time to build eating and activity habits that last:
- protein at every meal and plenty of vegetables and fibre
- regular strength training to protect muscle, which helps your body burn energy
- regular sleep and a plan for stress and emotional eating
See what to eat on Mounjaro to protect your muscle.
4. Keep monitoring Weigh yourself regularly after stopping. Agree with your prescriber in advance how much regain would prompt a conversation about restarting.
5. Consider support Programmes that include dietitians or coaching, such as Juniper, Second Nature or Numan, focus on habits for life after medication. Second Nature offers a no-regain guarantee on its 12-month programme; check the terms.
How long do people stay on these medicines?
- NHS Wegovy is usually prescribed through specialist weight management services for a maximum of two years.
- NHS Mounjaro has no fixed end date in the NICE guidance, but should be stopped if you haven't lost at least 5% of your weight after 6 months on the highest dose you can tolerate. See Mounjaro on the NHS.
- Privately, there's no time limit. You and your prescriber decide.
Can you switch instead of stopping?
Yes. Some people switch from Mounjaro to Wegovy, or to a weight loss pill, to cut costs or because of side effects. Wegovy at 2.4mg costs from £161 a month against £269.99 for Mounjaro 15mg at the cheapest providers, and the Wegovy pill and Foundayo cost from about £90 to £100 a month at the starter dose. Your prescriber will advise on the right starting dose when you switch. See Wegovy vs Mounjaro cost and weight loss pill prices.
What about restarting?
If you regain weight, you can usually restart after a new consultation. You'll often need to start again at a lower dose and build up, because your body may no longer be used to the medicine. That means going through the side-effect phase again.
Keep reading
- Mounjaro side effects: what to expect
- Mounjaro and Wegovy: what to expect
- How much do weight loss injections cost?
- Weight loss pill vs injection
- Mounjaro on the NHS in 2026
Frequently asked questions
Will I put weight back on after stopping Mounjaro?
Most people do. In SURMOUNT-4, people who stopped regained 14% of their body weight over a year, although they remained about 10% lighter than when they started.
How quickly does weight come back after stopping Wegovy?
In STEP 1, people regained about two-thirds of the weight they'd lost within a year of stopping.
Should I taper off Mounjaro or Wegovy?
There's no official UK tapering schedule. Some prescribers step the dose down gradually or use a lower maintenance dose. Agree a plan with your prescriber rather than changing your dose yourself.
Do I have to take Mounjaro or Wegovy forever?
Not necessarily, but trials suggest the weight loss is best maintained while you keep taking it. Many people and their prescribers treat it as a long-term medicine, like those for blood pressure.
Can I restart Mounjaro after stopping?
Usually yes, after a new consultation. You may need to start at a lower dose again.
This article is for information only and is not medical advice. CompareTheJab is an independent comparison website, not a pharmacy or medical service. Always speak to a qualified prescriber before starting, stopping or switching any medicine.
Prices were checked on each provider's own website on 3 November 2026 and change often. Always confirm the price at checkout. Some links on this page are affiliate links, which never affect how we rank providers. Read our affiliate policy and how we compare providers.
