The 30-second summary
- Stopping usually brings much of the weight back. In trials, people regained about two-thirds of what they had lost on semaglutide within a year of stopping, and about half of what they had lost on tirzepatide.
- This is biology, not a lack of willpower. Appetite hormones shift towards eating more after weight loss, and the body burns a little less.
- Plan it with your prescriber. Staying on, stepping down, or stopping with a plan for exercise, self-monitoring and a return route are all better than stopping and hoping.
What the trials show
Three large trials looked at what happens when people stop.
| Trial | Weight lost before the switch | Switched to placebo | Stayed on the medicine |
|---|---|---|---|
| STEP 1 extension, semaglutide 2.4 mg | 17.3% over 68 weeks | Regained about two-thirds of the loss in a year, ending 5.6% below the start | Not tested: everyone stopped |
| STEP 4, semaglutide 2.4 mg | 10.6% over 20 weeks | Regained 6.9% of body weight over 48 weeks | Lost a further 7.9% |
| SURMOUNT-4, tirzepatide 10 or 15 mg | 20.9% over 36 weeks | Regained 14.0% of body weight over 52 weeks | Lost a further 5.5% |
In the STEP 1 extension, most of the improvements in heart and metabolic health measures also moved back towards where they started. The authors wrote that the findings confirm obesity is a chronic condition and suggest ongoing treatment is needed to keep the improvements in weight and health.
In SURMOUNT-4, 89.5% of people who stayed on tirzepatide kept at least 80% of their weight loss, against 16.6% of those switched to placebo. Averages hide a range: some people regain little, others most of it.
Stopping is also common. A 2026 review in eClinicalMedicine reports that 50 to 65% of US adults without diabetes who are prescribed these medicines for weight stop within the first year.
Why the weight comes back
The medicine leaves your body over weeks. According to their prescribing information, semaglutide has a half-life of about a week and tirzepatide about 5 days, so levels fall gradually rather than overnight. We could find no study that pins down exactly when appetite returns after the last dose.
Appetite hormones push back. In a 2011 study in the New England Journal of Medicine, people who lost weight by diet still had lower levels of the fullness hormones leptin, peptide YY and cholecystokinin, higher levels of the hunger hormone ghrelin, and more hunger, a full year later. The 2026 review describes the same pattern once GLP-1 medicines stop: the appetite suppression reverses and these hormones shift towards eating more.
The body burns a little less. The same review describes adaptive thermogenesis: after weight loss, by any method, resting energy use can fall by more than the smaller body size alone would predict, and this can last months or years.
Old habits and pressures return. The review also lists emotional and stress-related eating, portion sizes and snacking drifting back, and weight stigma among the drivers of regain.
None of this is a personal failure. It is the predictable behaviour of a system the medicine was managing. (See your set point and when food noise comes back.)
What helps, and how good the evidence is
Staying on, or stepping down. The clearest evidence. STEP 4 and SURMOUNT-4 show continuing works better than stopping. SURMOUNT-MAINTAIN, published in 2026, found that people who dropped tirzepatide to 5 mg for a year ended 16.6% below their starting weight, against 21.9% for those who stayed on their full dose and 9.9% for those who stopped. (See staying on a lower GLP-1 dose.)
Tapering. Not yet tested properly. The 2026 review found no randomised trial of tapering or transition plans after stopping. It notes that gradual dose reduction might, in theory, let appetite return more slowly, and that small observational studies suggest individualised or tapered dosing may help some people hold their weight on lower doses.
Exercise. The best evidence for life after the medicine. In a Danish trial, 195 adults lost about 13 kg on a low-calorie diet and were then randomly assigned to a year of supervised exercise, the daily GLP-1 medicine liraglutide, both, or placebo. A year after treatment ended, weight regain was 6.0 kg larger in those who had stopped liraglutide alone than in those who had stopped supervised exercise. People who had had both were more likely to still be at least 10% below their starting weight. It was a small follow-up, with 109 people, and liraglutide is an older medicine, but the direction is clear. (See strength training on a GLP-1.)
Strength training and muscle. The 2026 review says resistance training helps maintain muscle mass and metabolic capacity, and that physical performance is generally preserved when it is kept up. (See keeping muscle on a GLP-1.)
Weighing yourself and keeping track. The review calls self-monitoring and accountability consistent predictors of long-term success: regular self-weighing, food logging and activity tracking help people spot drift early.
Psychological support. Cognitive behavioural therapy is, in the review's words, the most established framework for long-term weight management, with mindfulness and acceptance-based approaches alongside it.
Protein. Useful, but not a fix on its own. In the DIOGENES study, a higher protein diet meant about 0.9 kg less regain over 26 weeks, a small difference. In the PREVIEW trial, a high-protein diet improved appetite measures but not weight regain. Protein still matters for fullness and for muscle. (See protein on a GLP-1.)
A plan to take to your prescriber
A 2026 European consensus statement recommends that decisions to start, increase, delay, pause, reduce or stop these medicines are made together, weighing the physical and psychological risks of treating against not treating. A plan has four parts.
- How. Stop, step down to a lower dose, or stay on. If cost or side effects are the reason, say so: there may be options short of stopping.
- A trigger. Agree in advance what amount of regain would prompt a conversation about restarting or going back up. SURMOUNT-MAINTAIN built one in, restarting the medicine for anyone who regained more than half of what they had lost. That was a trial rule, not a target for you, but it shows the idea.
- What you will keep doing. Strength training, protein at each meal, regular weighing, and enough sleep.
- A way back. Who you will contact, and how quickly you could restart, if the trigger is reached.
If you are stopping to try for a baby, the prescribing information advises stopping semaglutide at least 2 months before a planned pregnancy and tirzepatide at least 1 month before. (See GLP-1 medicines and birth control.)
What to do with this
Keeping weight off asks something specific of you, and it helps to see the number. If you enter a goal weight at or below your current weight, the calculator gives you a maintenance calorie target rather than a deficit, along with a protein floor.
Sources
- Wilding JPH, et al. Weight regain and cardiometabolic effects after withdrawal of semaglutide: The STEP 1 trial extension. Diabetes Obes Metab 2022. PubMed
- Rubino D, 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. PubMed
- Aronne LJ, et al. Continued Treatment With Tirzepatide for Maintenance of Weight Reduction in Adults With Obesity: The SURMOUNT-4 Randomized Clinical Trial. JAMA 2024. PubMed
- Horn DB, et al. Tirzepatide for maintenance of bodyweight reduction in people with obesity in the USA (SURMOUNT-MAINTAIN): a multicentre, double-blind, randomised, placebo-controlled trial. Lancet 2026. PubMed
- Moiz A, et al. Weight maintenance after discontinuation of GLP-1 therapies. eClinicalMedicine 2026. PubMed
- Sumithran P, et al. Long-term persistence of hormonal adaptations to weight loss. N Engl J Med 2011. PubMed
- Lundgren JR, et al. Healthy Weight Loss Maintenance with Exercise, Liraglutide, or Both Combined. N Engl J Med 2021. PubMed
- Jensen SBK, et al. Healthy weight loss maintenance with exercise, GLP-1 receptor agonist, or both combined followed by one year without treatment: a post-treatment analysis of a randomised placebo-controlled trial. eClinicalMedicine 2024. PubMed
- Dobbie LJ, et al. Nutritional, functional, and psychological considerations for incretin-based therapies in adults: an EASO, EFAD, and ECPO Consensus Statement. Lancet Diabetes Endocrinol 2026. PubMed
- Wegovy 2.4 mg FlexTouch solution for injection in pre-filled pen: Summary of Product Characteristics. electronic medicines compendium. emc
- Mounjaro KwikPen solution for injection in pre-filled pen: Summary of Product Characteristics. electronic medicines compendium. emc
Medical disclaimer: Articles in the foodose research library are educational, not medical advice. Decisions to stop, continue, reduce or restart a medicine are for you and your prescriber. See our full medical disclaimer.