People who stop using the weight-loss drug Mounjaro (tirzepatide) not only tend to regain lost weight but also lose related health improvements, according to new research.
The study, published in JAMA Internal Medicine, analysed data from the Surmount-4 clinical trial. Participants first took tirzepatide for 36 weeks, then were split into two groups: one continued the drug for another year, while the other switched to a placebo.
Among those who stopped the medication after losing at least 10% of their body weight, 82% regained 25% or more of the weight they had lost within a year. Researchers also found that as weight returned, so did higher blood pressure, increased “bad” cholesterol, larger waist circumference, and worse blood sugar control.
Experts said the findings were expected, as excess weight is closely tied to these health risks. Professor Naveed Sattar of the University of Glasgow warned that stopping the drug may also remove potential protection against heart problems seen in previous studies.
Researchers stressed the importance of long-term weight management, either through ongoing medication or sustained lifestyle changes. Other experts noted that some people do not build lasting healthy eating and exercise habits while on the drug, making relapse more likely once treatment stops.
Separately, early research suggests women who stop weight-loss drugs before or during pregnancy may face higher risks of complications, though experts caution more evidence is needed.
