People who stop using the weight-loss drug Mounjaro often regain weight and lose key health improvements, according to new research.
The study found that stopping tirzepatide, the active ingredient in Mounjaro, not only leads to weight regain but also reverses benefits such as lower blood pressure, improved blood sugar control and reduced “bad” cholesterol levels.
Researchers analysed data from the Surmount-4 clinical trial, which followed adults with obesity or overweight plus related health conditions. All participants used tirzepatide for 36 weeks before being split into two groups: one continued the drug, while the other switched to a placebo for a further year.
Among those who stopped the medication after achieving significant weight loss, 82% regained at least a quarter of the weight they had lost within a year. Greater weight regain was linked to larger reversals in waist size, cholesterol, blood pressure and blood glucose. Those who regained 75% or more of their lost weight saw their health measures return to starting levels.
Experts said the findings were expected, as weight regain is known to worsen cardiometabolic health. They warned that stopping the drug could also remove possible heart-protective effects seen in other studies.
Researchers stressed the importance of long-term weight management, combining lifestyle changes with ongoing treatment where appropriate. Some experts noted that weight-loss injections may not always lead to lasting healthy habits, making it easier for people to revert to previous diets and activity levels after stopping.
Separate research suggested that women who stop these medications before or during early pregnancy may face higher risks of pregnancy complications, though experts cautioned that more research is needed to confirm a direct cause.
