How Long Can You Stay on GLP-1 for Weight Loss? (October 2026)

01 · The short answer

How long can you stay on GLP-1 for weight loss?

You can stay on a GLP-1 for weight loss for as long as your prescriber agrees it is working and suitable for you. The licensed medicines are prescribed alongside a reduced-calorie diet and increased physical activity. The review points, not the calendar, are what matter.

The main timeframe in the trial evidence is 72 weeks. In the SURMOUNT-1 trial of 2,539 adults, people taking tirzepatide alongside diet and exercise lost on average 15% of their body weight on 5mg, 19.5% on 10mg and 20.9% on 15mg over 72 weeks, compared with 3.1% with lifestyle changes alone.² These are trial averages, and individual results vary. It is a measurement window, not a limit on treatment.

For Mounjaro specifically, see how long you can use Mounjaro for weight loss.

02 · What to decide

The two decisions you are actually facing

The first decision is whether this medicine is right for you at all. The second is what you will do at each review: continue, hold, adjust or stop. Most of the anxiety about duration comes from treating these as one decision made on day one. In practice they are made repeatedly, with your prescriber, as your results and tolerance become clear.

If you are ready to start, the Mounjaro pen begins at the 2.5mg starting dose. All six doses are in stock. You can also read about the wider weight loss clinic service.

Related guides: How Long Do You Stay On Mounjaro For Weight Loss Week 1 and Orlistat Weight Loss UK - How Long Can You Take It? and How Long Do You Stay On Mounjaro FAQ and Glp 1 infographic.

03 · The 16-week review

The 6-month review: your first real decision point

Treatment response is reviewed by your prescriber: if you have lost less than 5% of your starting weight after 6 months on the highest dose you can tolerate, your prescriber will discuss whether continuing or stopping is right for you.¹

Note the phrase 'highest tolerated dose'. Everyone starts Mounjaro on 2.5mg once a week, and that starting dose is about letting your body adjust, not about weight loss itself. The dose then steps up at a minimum of 4-week intervals, depending on how you respond and tolerate it.¹

That is why the review is a conversation. Your prescriber looks at your trend, your tolerance, your dose and your day-to-day life. The outcome is not automatically 'stop'. It can be to continue, to adjust, or to stop, and each is a legitimate result of the review.

The same logic applies if you are on a different GLP-1 medicine. Wegovy, for example, steps up after 4 weeks on each of 0.25mg, 0.5mg, 1mg and 1.7mg, and the 2.4mg maintenance dose starts from week 17, so the early months are also about titration there. Ask your prescriber how the review works for the specific product you use.

04 · Trial durations explained

What the 72-week trial window does and does not tell you

The 72-week figure tells you how long the main weight-loss measurements ran, not how long you are allowed to stay on treatment. Trials need an end point so researchers can compare groups. Real-world treatment is reviewed continuously and is not cut off at the end of a trial.

The same trial found that at 72 weeks, 85% of participants on 5mg, 89% on 10mg and 91% on 15mg had lost at least 5% of their body weight. Half of participants on 10mg and 57% on 15mg lost at least 20% of their body weight.² These are trial averages, treatment works alongside diet and activity, and individual results vary.

Notice what a trial window cannot say. It cannot tell you what your own result will be. It also cannot tell you what is right for you after the window closes. Those questions are for your prescriber, who has your history in front of them.

Trials measured results at 72 weeks — think in months, not days, and judge progress by trend, not individual weigh-ins.¹

05 · Short course or long term

Short course or long term: how to think about it

A short course is possible, because you can stop at any time. The honest trade-off is that the benefits measured in trials were measured while people were taking the medicine.

Weight management is described by prescribers as health management rather than appearance. That is partly because in trials, weight loss on tirzepatide came with average improvements in waist size, blood pressure, cholesterol and blood-sugar measures, and most participants with prediabetes returned to normal blood-sugar levels.² These are trial-average secondary outcomes, not promises. They do show why the question is rarely just 'how many kilos'.

A first year costs £2,711.88 if you stay on 5mg after your 2.5mg starting pen, up to £3,599.88 if you step up through every dose to 15mg. These are standard prices. A new customer's first order is £40 less, and every later order is £25 less (code DOSE25).

06 · Stopping GLP-1 safely

Stopping GLP-1: what happens and what to do

You can stop at any time, and nothing special needs doing once you have. Tirzepatide has a half-life of about five days, so after a final dose it takes roughly 4–5 weeks to clear the system — there is no way to speed this up, and nothing needs doing while it clears.¹

Tell your prescriber you are stopping. Agreeing the change with them lets them check how you are, discuss what comes next, and record the change.

• Agree the decision with your prescriber at a review, rather than drifting off treatment.
• Decide in advance how you will handle meals, portions and protein once the appetite effect fades.
• Keep weighing yourself on a consistent schedule so you see the trend early.
• Keep up the physical activity that has been part of your routine.
• Tell your prescriber if you want to restart. Repeat orders re-check suitability, and there is no auto-shipping.

07 · Never stretch or split doses

Why you should never stretch a pen or microdose to stay on longer

Altering doses outside the licence means unknown dosing accuracy and no safety data.¹

The pen itself is designed to prevent this. Each KwikPen contains four weekly doses.¹

If side effects are why you want to stretch, talk to your prescriber instead.

08 · Early months and plateaus

The early months: what to expect before you judge the course

The first few months are modest by design, so they are a poor basis for deciding how long to stay on. Three months in, most people are still on the lower rungs of the dose ladder, so trial-average losses at this stage are modest compared with the headline figures. A sensible 3-month expectation on a standard titration is mid single digits as a percentage of body weight, with wide individual variation.²

Slower early progress does not predict failure, since the dose you respond to may still be ahead of you. The 2.5mg starting weeks are about adjustment, and experiences differ widely: some people notice appetite change and early loss in week one, others feel little until a higher dose, and both are normal. Early loss includes water weight, so the trend over weeks matters more than any single weigh-in.¹

Do you eventually stop losing weight?

Yes, losing weight does slow, and that is expected rather than a failure. Weight loss on Mounjaro is not linear — plateaus of a few weeks are normal and expected as the body adapts to a lower weight.¹ Within the licence, the responses are to review food intake honestly because portions drift back up, protect protein and activity, check the basics such as sleep and alcohol, and discuss with your prescriber whether a dose step-up is appropriate if you are not yet at maximum.

A plateau is not a reason to double doses or add unlicensed products. Many people settle at a maintenance dose of 5mg, 10mg or 15mg, and higher is not automatically better.¹ Your prescriber will guide the right pace.

09 · NHS and private routes

NHS and private routes: does duration differ?

The review principle is the same on either route, because a prescriber decides whether continuing is right for you. What differs is how quickly you can start. Mounjaro is available on the NHS, but access is being phased in over several years. NICE recommends it for adults with a BMI of at least 35 plus at least one weight-related condition, and the NHS primary-care rollout began in June 2025 with the highest-need groups first (initially BMI 40+ with four or more qualifying conditions).⁴⁶ Full rollout is expected to take years, which is why many people who meet the licensed criteria choose regulated private treatment rather than waiting.

With us, ongoing monthly reviews, dose titration and follow-up assessments are carried out by the prescribing team, with side-effect support. Repeat orders re-check suitability, so continuing is never automatic. Our questionnaire is free, and the prescriber review is by a GPhC-registered prescriber, not a scoring script. Support is available Monday to Friday, 9am to 5pm. The free GLPTrackr app can help you track your journey over time.

10 · Questions for your prescriber

Questions to take to your prescriber

Mounjaro is a prescription-only medicine, supplied only after an online consultation reviewed by a GPhC-registered prescriber, and it is used alongside a reduced-calorie diet and increased physical activity. Individual results vary.

• What is my current trend, and is it in line with what you would expect at this dose?
• Should I hold this dose, step up or step down?
• What is our plan if I plateau?
• If I want to stop, how should I time it and what should I do with food and activity?
• If I stop and want to restart, what does that involve?

Report any new symptom to your prescriber and, if you wish, via the Yellow Card scheme.¹⁹ Keep pens in the fridge at 2–8°C and never freeze them. Once in use, a pen can be kept out of the fridge at a temperature not above 30°C for up to 30 days after first use, and must then be thrown away.¹

This page is information, not a substitute for medical advice.