Obesity medication: anticipating weight regain

Why can weight go back up?

These medicines work in particular on hunger and fullness. When their effect wears off, appetite can increase again, while the biological mechanisms that promote weight regain are still present.

This is not a sign of a lack of willpower. It is a reminder that obesity is a chronic disease, whose management may require long-term treatment.

What the studies show

After stopping semaglutide

In the STEP 1 trial extension, participants previously treated with semaglutide regained, on average, about two thirds of the weight they had lost in the year after stopping. Both the medicine and the trial’s structured lifestyle support had been stopped.

This does not mean that everyone regains all their weight, but it shows that maintaining weight loss without treatment can be difficult.

After stopping tirzepatide

In an analysis of SURMOUNT-4 published in a 2026 issue, 82% of the participants studied regained at least a quarter of the weight they had lost in the year after stopping. This analysis concerned people who had initially lost at least 10% of their weight.

This means a quarter of the weight lost, not a 25% increase in total body weight. For example, a quarter of a 20 kg loss is 5 kg.

These studies do not compare the two medicines directly: their protocols and populations differ.

What do recent publications tell us?

A review published in the BMJ in 2026 confirms weight regain after these medicines are stopped and a gradual decline in some metabolic benefits.

Conversely, long-term treatment studies show that the benefits can be maintained. Trials published in 2026 also assess continuing treatment, adjusting the dose or switching to another medicine.

These options are discussed individually. A research finding does not mean that a strategy is available in Switzerland or suitable for every patient.

Planning ahead from the start

Before you start, and then during follow-up, we discuss with you:

• the benefits you are looking for and how you respond to treatment;
• how well you tolerate it and its place over the long term;
• diet, physical activity and preserving muscle;
• practical or financial constraints that could lead you to stop;
• what to do if your appetite or weight increases again.

Gradually reducing the dose or spacing out injections should not be presented as a guarantee against weight regain. Any adjustment is decided with the prescriber.

What is the role of surgery?

Surgery can be discussed when it is indicated, depending on your health and your history. There is no need to wait for substantial weight regain before reassessing the options.

Medication and surgery can also complement each other. Surgery itself requires long-term follow-up and does not rule out weight regain.

Medication and surgery: complementary approaches

If you are thinking of stopping

Talk to your doctor so that the next steps can be planned. The aim is to arrange follow-up and a suitable strategy, rather than leaving you alone to cope with returning hunger or rising weight.

Medical review of the French version: Dr Pierre Fournier

Scientific sources and references

Sources accessed on 15 October 2026.

1. 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;24(8):1553-64. doi:10.1111/dom.14725. Population: adults with overweight or obesity, without diabetes (subgroup of 327 STEP 1 participants). Duration: 68 weeks of treatment, then 52 weeks of observation after stopping the medicine and the lifestyle support. View source
2. Horn DB, Linetzky B, Davies MJ, et al. Cardiometabolic parameter change by weight regain on tirzepatide withdrawal in adults with obesity: a post hoc analysis of the SURMOUNT-4 trial. JAMA Intern Med. 2026;186(2):157-67. doi:10.1001/jamainternmed.2025.6112. Post hoc analysis. Population: 308 adults with obesity who had lost at least 10% of their weight after 36 weeks of tirzepatide and were then switched to placebo. Duration: 52 weeks of observation after stopping (weeks 36 to 88). Published in the February 2026 issue. View source
3. West S, Scragg J, Aveyard P, et al. Weight regain after cessation of medication for weight management: systematic review and meta-analysis. BMJ. 2026;392:e085304. doi:10.1136/bmj-2025-085304. Systematic review and meta-analysis of 37 studies (9,341 participants), mean follow-up of 32 weeks after stopping. The times to return to baseline values proposed by the authors are model-based projections, not observations. View source
4. Ryan DH, Lingvay I, Deanfield J, et al. Long-term weight loss effects of semaglutide in obesity without diabetes in the SELECT trial. Nat Med. 2024;30(7):2049-57. doi:10.1038/s41591-024-02996-7. Population: 17,604 adults with overweight or obesity, established cardiovascular disease and no diabetes. Duration: semaglutide treatment for up to 4 years. View source
5. Horn DB, Aronne LJ, Wharton S, 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;407(10545):2305-18. doi:10.1016/S0140-6736(26)00656-2. Population: 378 adults with obesity in the United States, after 60 weeks of tirzepatide. Comparison: continuing the dose, reducing the dose or placebo, for 52 weeks. Trial funded by the manufacturer. View source
6. Aronne LJ, Horn DB, le Roux CW, et al. Orforglipron for maintenance of body weight reduction: the double-blind, randomized phase 3b ATTAIN-MAINTAIN trial. Nat Med. 2026;32(7):2679-87. doi:10.1038/s41591-026-04386-7. Population: 376 adults in the United States, after 72 weeks of injectable semaglutide or tirzepatide. Comparison: switching to orforglipron, an oral medicine, or placebo, for 52 weeks. Trial funded by the manufacturer. View source