People who stop using the weight-loss drug Mounjaro (tirzepatide) tend to regain weight and lose associated health benefits, including improvements in blood pressure and “bad” cholesterol, according to new research.
Analysis of the Surmount-4 clinical trial found that among participants who stopped the drug after 36 weeks, 82% regained at least 25% of the weight they had lost within a year. Those who regained the most weight also saw reversals in waist size, cholesterol, blood pressure and blood sugar, often returning to pre-treatment levels.
Experts say the results are not surprising, as excess weight is closely linked to poorer cardiometabolic health. Professor Naveed Sattar of the University of Glasgow noted that stopping the drug may also remove its protective effects against serious heart outcomes.
The study, published in JAMA Internal Medicine, suggests that long-term weight maintenance likely requires continued treatment plus sustained lifestyle changes. Some experts warned that weight-loss injections may not always help people build healthier eating and exercise habits, making rebound weight gain more likely once the medication is stopped.
Separate research has also suggested that stopping similar drugs before or during pregnancy may be linked to higher pregnancy risks, though experts caution that more research is needed to confirm this.
