How long Mounjaro is taken and what happens when you stop
The question is usually asked too late, and the answer changes the way you look at the whole treatment. What withdrawal studies show about the weight regained, how quickly and why it happens — with the published figures, not impressions.
English translation of content medically reviewed in Romanian by Dr. Claudiu Ruscu, intensive care physician (anaesthesia & intensive care)· Romanian text reviewed 20 September 2026
This does not mean "treatment for life", and it is not a decision taken from an article. It means that the question about stopping is worth asking at the first consultation, not the last.
How much weight is lost, and over what period?
The authorisation trials lasted 68-72 weeks, and the weight loss was not linear: faster at first, slowing progressively towards a plateau. For tirzepatide, the average weight loss at 72 weeks was 15.0% at the 5 mg dose and 20.9% at 15 mg, according to SURMOUNT-1.
The question "how much will I lose per month" has no answer from the trials, because the pace changes over the course of the treatment. A monthly average calculated from the final figure would misdescribe both the beginning and the end.
What do the withdrawal studies show?
These are the studies that matter for the question in the title, and they are less well known than the authorisation trials.
| Study | Design | Continued | Switched to placebo |
|---|---|---|---|
| SURMOUNT-4 | 36 weeks of tirzepatide, then 52 weeks randomised | about 5.5% further loss | about 14% regained |
| STEP-4 | 20 weeks of semaglutide, then 48 weeks randomised | about 7.9% further loss | about 6.9% regained |
SURMOUNT-4 is published in JAMA, 2024, and STEP-4 in JAMA, 2021.
A separate follow-up, one year after stopping semaglutide, found that participants had regained about two thirds of the weight they had previously lost, and some of the improvements in cardiometabolic factors had returned towards baseline values — Diabetes, Obesity and Metabolism, 2022.
Why is the weight regained?
Because the mechanism disappears with the medicine, while the body's adaptations remain.
The effects on gastric emptying and on the fullness signals stop after the medicine is stopped, so portions return. At the same time, a body that has lost weight burns fewer calories than before and maintains hormonal changes that favour food intake. The combination pushes weight back up, and it does so without the person feeling that they have given anything up.
It is therefore not a matter of discipline. It is what happens when an intervention that acted on a physiological mechanism is withdrawn. The same logic applies to stopping any treatment that controls a parameter without curing the cause: the parameter comes back.
It is also worth saying what the cited studies do not show: they compare continuation with placebo, not continuation with a structured maintenance programme without medication. What would happen in the second case remains an open question, and anyone who presents you with a certain answer in either direction is going beyond the data.
Why is long-term treatment being discussed?
Because current guidelines approach obesity as a chronic condition, not as an episode that resolves and ends. From this perspective, the question "how long is it taken" is closer to "how long is blood pressure medication taken" than to "how long is an antibiotic taken".
The analogy has a limit worth stating: for antihypertensive treatment there are decades of data over long periods, whereas for injectable weight treatment, in this indication, the very long-term data are still accumulating. The studies cited above cover about two years in total, not ten.
What follows in practice: the decision to continue or to stop has no standard answer and is reassessed periodically, with your treating doctor, depending on the result, tolerability and your overall medical situation.
What is monitored along the way?
There is no single scheme — it is set by your treating doctor, depending on your situation and your other conditions. The elements that usually come up:
- weight and waist circumference, at set intervals, not daily;
- blood pressure;
- blood glucose, especially in people with diabetes or prediabetes;
- the lipid profile;
- kidney function, especially if there have been episodes of vomiting or loose stools;
- digestive tolerability and its impact on fluid and food intake;
- in people with diabetes, an eye examination, because of the warning about retinopathy.
What is not part of the monitoring: the number on the scales read daily. It varies normally by 1-2 kg from one day to the next and cannot distinguish a real trend from noise.
What does this mean in practice?
Three consequences, all to be discussed with your treating doctor, not decided alone:
For the periods when oral intake of fluids and food drops, whether at the start or at a change of schedule, what can be done at home is described in the article on hydration and food intake. And if the reason you are thinking of stopping is that you are not seeing results, it is worth first reading why I am not losing weight on Mounjaro.
In short
- There is no fixed treatment duration set in advance; it is decided by your treating doctor, according to the individual situation.
- In SURMOUNT-4, those who continued the treatment lost about a further 5.5% over 52 weeks, and those switched to placebo regained about 14%.
- In STEP-4, continuation brought about a further 7.9% loss, and switching to placebo about 6.9% of weight regained.
- One year after stopping semaglutide, participants had regained about two thirds of the weight they had previously lost.
- Weight returns because the effects on fullness stop with the medicine, while the lower calorie needs of a lighter body remain.
- The decision to continue or to stop is reassessed periodically with your treating doctor, depending on the result, tolerability and your overall medical situation.
This article is for information only and does not replace a medical consultation. The duration of treatment and the decision to stop belong solely to your treating doctor.
Frequently asked questions
- How long is Mounjaro taken?
- There is no fixed duration set in advance. It is decided by your treating doctor, according to the individual situation, the result and tolerability. The authorisation trials lasted 68-72 weeks, and the maintenance studies followed participants for about a further year.
- What happens if I stop the treatment?
- Withdrawal studies show a substantial regain of the weight lost. In SURMOUNT-4, those switched to placebo regained about 14% over 52 weeks. One year after stopping semaglutide, participants had regained about two thirds of the weight they had lost.
- How much weight do you lose with Mounjaro?
- In SURMOUNT-1, the average weight loss after 72 weeks was 15.0% of starting weight at the 5 mg dose and 20.9% at 15 mg, compared with 3.1% in the placebo group. These are group averages, obtained together with advice on diet and physical activity.
- Why does the weight come back after stopping?
- Because the effects on gastric emptying and on the fullness signals stop with the medicine, while a body that has lost weight burns fewer calories and maintains hormonal changes that favour food intake.
- Can I stop the treatment on my own?
- The decision belongs to your treating doctor. Stopping on your own initiative is not dangerous in itself, but it happens without any maintenance plan — exactly the moment when the plan matters most.
More in Guides
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References
The studies below support the statements on mechanism, pharmacokinetics and safety on this page. They do not support a guaranteed therapeutic outcome — each one is followed by its limitation.
[1] Jastreboff AM, Aronne LJ, Ahmad NN, et al. Tirzepatide Once Weekly for the Treatment of Obesity. N Engl J Med. 2022.
randomised trial · sample: 2539 · PMID 35658024
Limitation: All participants also received diet and physical-activity counselling, so the figures describe the combination, not the substance alone. People with type 2 diabetes were excluded. Follow-up stopped at 72 weeks, with no information on what happens after stopping. Funded by the manufacturer.
[2] Aronne LJ, Sattar N, Horn DB, et al. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. JAMA. 2024.
randomised trial · sample: 670 · PMID 38078870
Limitation: Randomisation was done only among people who already tolerated the treatment after 36 weeks, so the group is selected by the very criterion that matters. Follow-up after randomisation lasts 52 weeks and says nothing about the course over several years. Funded by the manufacturer.
[3] Rubino D, Abrahamsson N, Davies M, et al. Effect of Continued Weekly Subcutaneous Semaglutide vs Placebo on Weight Loss Maintenance in Adults With Overweight or Obesity: The STEP 4 Randomized Clinical Trial. JAMA. 2021.
randomised trial · sample: 803 · PMID 33755728
Limitation: The initial period was only 20 weeks, much shorter than a usual treatment, so the comparison starts from incomplete weight loss. Only people who had reached the target dose were randomised, so those who did not tolerate it are excluded from the result. Funded by the manufacturer.
[4] Wilding JPH, Batterham RL, Davies M, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes Obes Metab. 2022.
randomised trial · sample: 327 · PMID 35441470
Limitation: An extension of the STEP 1 trial, with 327 of the 1,961 original participants — those who agreed to further follow-up are not necessarily representative of the whole group. There was no group that continued treatment, so the comparison is with each person's own earlier value, not with an alternative.
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