Study: Weight-Loss Drugs Reduce Body Weight but Do Not Improve Quality of Life

Anti-obesity medications are becoming increasingly popular worldwide, but a new study suggests that while they help people lose weight, they rarely improve quality of life after one year of treatment.

Over the past year, millions of people have used weight-loss medications such as Ozempic and Mounjaro. However, new research indicates that the benefits may extend little beyond a lower number on the scale.

The study, published in The BMJ, analyzed 262 clinical trials involving nearly 100,000 participants and 19 different medications.

Researchers found that greater weight loss was consistently associated with higher rates of side effects and treatment discontinuation, Euronews reports.

"Most active treatments do not lead to clinically meaningful improvements in quality of life, and only a few demonstrate cardiovascular benefits," the study authors wrote.

During the trials, participants completed standardized questionnaires measuring health-related quality of life. Researchers compared changes in these scores among people taking weight-loss medications with those who relied on lifestyle modifications alone. They found no clinically significant improvements in quality of life for any of the major treatment options.

Among all therapies evaluated, tirzepatide—the active ingredient in Mounjaro and Zepbound—and CagriSema, which has not yet been approved for clinical use, produced the greatest weight loss in adults with overweight or obesity.

According to the authors, subcutaneous semaglutide, the active ingredient in Ozempic and Wegovy, currently has the strongest evidence for reducing mortality and the risk of major cardiovascular events.

However, both tirzepatide and semaglutide were also associated with an unfavorable reduction in lean body mass—the body's weight excluding fat tissue. Low lean mass has been linked to an increased risk of falls, bone fractures, and premature death.

The researchers note that most of the trials included in the analysis had relatively short follow-up periods and emphasize that further studies are needed to fully understand the long-term effects of these newer medications.

Meanwhile, independent experts caution that the findings related to quality of life should be interpreted carefully because methods of measuring quality of life vary considerably.

"Quality of life is a complex concept that differs from person to person. Standardized assessment scales provide valuable information, but they may not capture every aspect of treatment that matters to people living with obesity," said Marie Spreckley of the University of Cambridge, who was not involved in the study.

Obesity is increasingly recognized as a complex chronic disease. The study authors warn that evaluating treatment success solely by weight loss may oversimplify both the benefits and the risks of therapy while reinforcing the stigma surrounding obesity.

"This study confirms what we already knew: some medications produce substantial weight loss, but losing weight alone does not mean every aspect of health improves," said José M. Ordovás of Tufts University, who was not involved in the research.

"The scale tells only part of the story—not the whole story," he added, emphasizing that the success of obesity treatment should be measured not only in kilograms lost, but also by overall health, physical functioning, and quality of life.