Yo-yo effect is particularly bad
Researchers find new disadvantage of popular drugs
January 9, 2026 – 2:27 p.mReading time: 3 min.
Weight loss medications help with weight loss, but often only temporarily. A new study shows that those who stop treatment regain weight significantly more quickly on average than after diet programs.
Whether modern weight loss injections such as Ozempic and Wegovy or older substances such as Orlistat or Fenfluramine: More and more people are turning to weight loss medications to lose weight. According to a report from the health insurance company Barmer from 2025, the number of therapies with weight loss injections in Germany approximately doubled between 2020 and 2024.
Initially the success seems to be great. But a current systematic review from the University of Oxford paints a sobering picture: after stopping the medication, the weight usually goes back up quickly – faster than after classic diet and exercise programs. The study was recently published in the British Medical Journal.
For the review, the scientists analyzed 37 studies with a total of 9,341 overweight or severely overweight (obese) adults. On average, they had received a weight loss drug for 39 weeks, including modern GLP-1 receptor agonists such as semaglutide (in Ozempic and Wegovy), liraglutide (in Saxenda) or tirzepatide (in Mounjaro). After stopping the medication, participants were followed for an additional 32 weeks on average.
Particularly striking: Compared to behavior-oriented programs – such as diets or exercise programs – weight gain was significantly faster after the end of drug treatment. On average, the difference was 0.3 kilograms per month – regardless of how much weight the participants had previously lost.
According to study author Dimitrios Koutoukidis, the reason for this probably lies in the nature of the treatment. In a statement about the study, he explains: “People taking medication do not need to consciously change their diet to lose weight. When they stop taking the medication, they may not have developed the practical strategies that could help them maintain weight.”
