Coming off Mounjaro or Wegovy: what we know about weight regain

A year after their last injection, participants in the STEP 1 trial had put back two thirds of the weight they lost on semaglutide. The result, published in 2022, planted a worry that now shows up in what people search for: "coming off Mounjaro", "how to come off Mounjaro", "Wegovy maintenance dose", "do I have to stay on it for life".

The question is a fair one and the answer does not fit in a sentence. Yes, regain is the rule in the trials. No, it is neither total nor the same for everyone, and its size depends on what you compare. This article describes what the studies measured. It does not tell anyone whether to stop, continue or adjust a treatment: that decision is made with the clinician who prescribes it.

What the withdrawal trials found

Three trials serve as the reference, and all show clear weight regain in the year after stopping.

The first is the STEP 1 extension, published in Diabetes, Obesity and Metabolism in 2022. After 68 weeks of Wegovy (semaglutide) at 2.4mg, both the treatment and the lifestyle support were withdrawn, and 327 participants were followed for a further year. They had lost 17.3% of their weight on average. A year later they had regained 11.6 percentage points. They were left with a net loss of 5.6% from where they started.

The second, STEP 4, went about it differently. All participants first received semaglutide for 20 weeks, then a random draw decided who carried on and who switched to placebo, with nobody knowing which group they were in. Over the next 48 weeks, weight fell a further 7.9% in those who continued and rose by 6.9% in the others.

The third concerns Mounjaro (tirzepatide). In SURMOUNT-4, 670 adults who had lost 20.9% of their weight in 36 weeks were split between continuing treatment and placebo. A year on, the placebo group had regained 14%, while the treated group had lost another 5.5%.

One detail matters. In STEP 4 and SURMOUNT-4, advice on diet and physical activity continued in both groups. The regain happened in spite of that support.

An average, not a destiny

These figures are averages, and they describe no individual patient's path. In SURMOUNT-4, 16.6% of participants switched to placebo had kept at least 80% of their weight loss a year later. That is small beside the 89.5% in the group that stayed on treatment. It is not nothing.

The same trials also show that not everything is undone by the end of follow-up. When SURMOUNT-4 finished, the placebo group still weighed 9.9% less than at the very start of the trial. In the STEP 1 extension, the net loss was still 5.6% at week 120, more than two years after the first injection.

What happens after that? A team at the University of Oxford tried to project it by pooling 37 studies and 9,341 participants, across all weight loss medicines, in a meta-analysis published by the BMJ in January 2026. After stopping an obesity medicine, weight climbs by an average of 0.4kg a month. For semaglutide and tirzepatide, which produce bigger losses, the estimated rate reaches 0.8kg a month, or 9.9kg in the first year, a little over a stone and a half, and the model places the return to starting weight about a year and a half after stopping.

That last estimate comes with a caveat the authors spell out themselves. For these two medicines, no follow-up went beyond 52 weeks: past that point the curve is an extrapolation. The same work found that regain is faster after a medicine than after a behavioural weight management programme, where the return to starting weight is projected at 3.9 years, against 1.7 years for medicines as a whole.

Why the weight comes back

The weight returns because the medicine stops acting and the body has not changed its settings.

The first mechanism is simple. These molecules mimic a fullness hormone for as long as they circulate. According to its product information, semaglutide remains in the bloodstream for about seven weeks after the last 2.4mg dose. Once that time is up, the extra signal goes out. The appetite many patients describe as having "come back overnight" is no longer being held in check by anything. People call it the return of food noise.

The second is older than these treatments. The body defends its weight. In 2011 an Australian team measured appetite hormones in 50 people before a diet, straight after it, and a year later. Twelve months after the weight loss, leptin and peptide YY, which rein in hunger, were still lowered; ghrelin, which drives it, was still raised, and the sensation of hunger with it. The study appeared in the New England Journal of Medicine.

Other researchers have put a number on that push. Working from a trial in which patients lost weight without knowing it, they calculated that appetite rises by about 100 kcal a day for every kilo lost, an effect more than three times greater than the fall in energy expenditure (Obesity, 2016). While the treatment is there, it masks that pressure. When it stops, the pressure makes itself felt again.

None of this is a failure of willpower, and UK guidance now reflects that. When NICE updated its quality standard on overweight and obesity in August 2025, it said that weight management "doesn't end when medication stops" and called for people to be monitored for at least a year after finishing treatment, with extra support offered if needed.

Heart health and blood sugar follow the same slope

The improvements measured in blood pressure, blood sugar and blood fats slip back as the weight returns. In the STEP 1 extension, most of the gains achieved over 68 weeks had drifted towards their starting level a year after stopping. The BMJ meta-analysis projects a return to baseline within a year and a half for all the markers it studied.

This is one of the things clinicians weigh when discussing how long treatment should last. On continued treatment the weight loss holds: in the STEP 5 trial it was 15.2% after two years of semaglutide (Nature Medicine, 2022).

What food and movement can do

No lifestyle habit has been shown to cancel the regain. Some soften it, and the strongest data concern physical activity.

A team in Copenhagen compared four maintenance strategies for a year after a diet: a supervised exercise programme, Saxenda (liraglutide), the two together, or a placebo. Then everything stopped and participants were seen again a year later. In the year without treatment, those who had received liraglutide alone regained 6kg more than those who had followed the exercise programme. At the end of the two years, the gap was 5.1kg in favour of the group that had combined the two, compared with liraglutide alone (eClinicalMedicine, 2024).

The trial is modest, with 109 people seen at the end, and it concerns an older medicine than semaglutide. Its message is still worth holding on to: exercise established during treatment seems to go on protecting afterwards.

On the food side, the reference remains the European Diogenes study, published in the New England Journal of Medicine in 2010. In 773 adults who had just lost weight, a diet slightly higher in protein and slightly lower in glycaemic index limited regain over 26 weeks, by about a kilo compared with the opposite diets. The effect is real and modest, and it has not been tested after a medicine. For what such a way of eating looks like day to day, see our GLP-1 diet guide and the 7-day diet plan built on it.

That leaves the question of muscle. In a sub-study of SURMOUNT-1, about a quarter of the weight lost on tirzepatide was lean mass (Diabetes, Obesity and Metabolism, 2025), a proportion close to that in the placebo group. Protein contributes to the maintenance of muscle mass, and strength training keeps it in use. We devote a separate article to muscle loss on these medicines.

Coming off Mounjaro or Wegovy is a clinical decision

The decision belongs to the patient and the prescriber, and the patient leaflets are direct about it. The one for Wegovy tells patients not to stop without speaking to their doctor. The one for Mounjaro adds that in type 2 diabetes, blood sugar may rise once treatment ends.

People come off a treatment for very different reasons: side effects, a planned pregnancy, the monthly cost of a private prescription, reaching a target, simply having had enough. On the NHS there may be a time limit as well, since NICE recommends Wegovy for a maximum of two years within specialist weight management services. None of these is discussed in the same way. As for the method, many patients ask whether it is better to step the dose down gradually, or to stay on a lower "maintenance dose". We found no randomised trial that settles the question, and the BMJ meta-analysis cannot answer it. It is for the prescriber to judge, case by case.

What the patient can do is arrive at the appointment with questions. What follow-up of weight and blood tests is planned for the months afterwards? What dietary support and what exercise should be in place before stopping, not after? How much regain should prompt a return visit? NICE's 2025 standard presses the same point: the period after treatment is to be planned for, with an action plan the person can put into practice if things start to slip.

One caution to finish. If appetite returns and the scales move, the response is a conversation with a clinician, never a pen bought through social media or a product promising the same effect naturally. Our piece on natural GLP-1 explains what food can and cannot do, and the guide to GLP-1 side effects covers what to watch for if treatment is restarted.

Frequently asked questions

Do you always put weight back on after coming off Mounjaro or Wegovy?

In the trials, the great majority of participants do, but not all and not to the same degree. In SURMOUNT-4, 16.6% of people switched to placebo had kept at least 80% of their weight loss a year later.

How much weight do people regain on average?

A meta-analysis published by the BMJ in 2026 estimates regain at 0.8kg a month after semaglutide or tirzepatide, nearly 10kg in the first year. In the STEP 1 extension, participants had regained two thirds of the weight lost a year after stopping.

How quickly does the weight come back?

Regain begins in the weeks after stopping and continues for at least a year. The return to starting weight is projected at about a year and a half for semaglutide and tirzepatide, though that is an extrapolation beyond 52 weeks of follow-up.

Do you have to stay on weight loss injections for life?

The trials show that weight loss holds for as long as treatment continues and slips back when it stops. How long to treat is decided with the prescriber, according to health, tolerance and each person's plans.

Are there withdrawal symptoms when you stop?

The product information for Wegovy and Mounjaro does not describe a withdrawal syndrome. What people feel is their previous appetite returning. In people with diabetes blood sugar can rise, which is why medical follow-up matters.

Does exercise limit weight regain?

It is the best-documented lever. In a Danish trial, people who had followed a supervised exercise programme regained markedly less weight, a year after stopping, than those who had received the medicine alone.

Can you restart treatment after stopping?

That is something only a prescriber can assess, taking account of why you stopped and how things stand now. Restarting should never be done on your own initiative or with a medicine obtained outside a registered pharmacy.

This article is for information only and is no substitute for advice from a healthcare professional. Never change your treatment without talking to your doctor.