Once Mounjaro is working, the next question is usually how long you can keep taking it. The short answer is that neither the UK licence nor NICE sets a fixed end date. What they set instead is a check on whether it is working for you. Here is what each says, what the longest trials show, and how your treatment is reviewed.
Does the Mounjaro licence set a time limit?
No. The UK product information for Mounjaro sets no maximum length of treatment. It licenses tirzepatide "for weight management, including weight loss and weight maintenance, as an adjunct to a reduced-calorie diet" and increased physical activity, so keeping weight off is part of what it is licensed for.
What the licence sets is a review point. If you have not lost at least 5% of your starting weight 6 months after reaching the highest dose you can tolerate, a decision is needed on whether to continue, taking into account the benefits and risks for you.
Staying on Mounjaro also does not mean staying on the top dose. The product information gives 5mg, 10mg and 15mg as the maintenance doses. Our guide on when to increase your Mounjaro dose explains how the steps are decided.
What does NICE say about how long to take Mounjaro?
NICE does not set a maximum length of treatment for tirzepatide, the medicine in Mounjaro. Its guidance, TA1026, makes the same 6 month check as the licence: if less than 5% of the starting weight has been lost after 6 months on the highest tolerated dose, decide whether to continue, taking into account the benefits and risks for the person.
NICE considered a long-term stopping rule and decided against one. The committee concluded that it was not appropriate to include a long-term stopping rule for tirzepatide, and it heard from experts that obesity is a chronic condition that needs long-term treatment. NICE's guidance also decides who can get Mounjaro on the NHS, which is a narrower group than the licence covers; see Mounjaro on the NHS.
What do the longest Mounjaro trials show?
The longest published results come from the SURMOUNT-1 trial, which followed people for 176 weeks. In this part of the trial (New England Journal of Medicine, 2025), 1,032 adults with obesity and prediabetes took tirzepatide 5mg, 10mg or 15mg once a week, or placebo, alongside diet and activity advice. At 176 weeks, their weight had fallen by an average of 12.3%, 18.7% and 19.7% on the three doses, compared with 1.3% on placebo. The most common side effects were stomach and bowel effects, mostly mild to moderate and mainly during the first 20 weeks while the dose was being increased, and no new safety concerns were found. Individual results vary.
In the SURMOUNT-4 trial (JAMA, 2024), 670 adults with obesity or overweight and without diabetes who had lost an average of 20.9% of their weight over 36 weeks on tirzepatide were randomly assigned to carry on or switch to placebo. Over the next 52 weeks, the weight of people who switched rose by an average of 14.0%, while those who carried on lost a further 5.5%. At 88 weeks, people who had switched were on average 9.9% below their starting weight, compared with 25.3% for those who carried on. Individual results vary.
What happens if you stop Mounjaro?
Most people regain weight after stopping, as SURMOUNT-4 shows, which is why stopping works best as a plan rather than a sudden decision. Appetite returns as the medicine clears, and the habits you have built matter most at that point. If you have type 2 diabetes, your blood sugar will need monitoring, so plan any stop with your prescriber. Our guide to what happens when you stop taking Mounjaro covers coming off it in detail.
How is long-term treatment reviewed at Solira?
Your treatment is reviewed regularly, and any decision to pause or stop it is made with you.
Treatment works alongside a reduced-calorie diet and regular activity. Aim for at least 150 minutes a week. Weight loss naturally slows over time, and stopping treatment without keeping lifestyle changes commonly leads to weight regain, so we review you regularly and plan any stop together.
We'll pause or stop treatment if it isn't working for you (less than 5% weight loss after a fair trial at your best-tolerated dose), if side effects persist despite adjusting, if your BMI falls below 20, or if you become pregnant. Treatment is reviewed regularly, and if longer-term therapy beyond our service is right for you, we'll help you transition to a prescriber-led pathway.