Achieving a healthy weight could become more and more attainable as time goes on

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The past few years have seen the emergence of highly effective drugs for treating obesity, and the hope is that the experimental treatments on trial in 2026 will prove to be even more effective.

“We are witnessing an exciting new chapter in obesity treatment that is improving the health and lives of many patients,” says Lora Heisler at the University of Aberdeen, UK. “Obesity fuels some of the world’s most serious diseases: cancer, heart disease and type 2 diabetes. Even a modest 5 per cent drop in body weight can lower those risks.”

The first of the blockbuster weight-loss drugs was a small protein called semaglutide. It was approved in 2017 as a diabetes treatment, marketed as Ozempic. In 2021, it was also approved for weight loss, sold as Wegovy.

Semaglutide mimics the action of a natural hormone called GLP-1 by binding to receptors in the brain and pancreas, reducing people’s appetite and slowing the passage of food through the stomach. It has also turned out to have direct cardiovascular benefits, in addition to the benefits due to weight loss, and may also help treat other conditions, such as drug and alcohol addictions. However, semaglutide can have side effects, including nausea and vomiting, that result in many people discontinuing its use.

In 2023, another drug called tirzepatide (sold as Mounjaro for diabetes) was also approved for weight loss, marketed as Zepbound. Tirzepatide improves on semaglutide by having a dual action: it mimics both GLP-1 and another hormone called GIP, which is involved in regulating energy use and storage. It has similar side effects to semaglutide.

In a head-to-head trial, semaglutide reduced people’s weight by 14 per cent, on average, over 72 weeks, whereas tirzepatide reduced it by 20 per cent. Other studies show that lost weight is typically regained if the drugs are discontinued.

Coming up next are more dual-action, and even triple-action, drugs. One that could be approved next year is CagriSema, a combination of a drug called cagrilintide – which makes people feel full by mimicking the action of a hormone called amylin – with semaglutide.

In a trial involving more than 3400 adults, people on CagriSema lost 20 per cent of their weight after 68 weeks, compared with 15 per cent for semaglutide alone and 12 per cent for cagrilintide alone. That suggests it is on par with tirzepatide, though various trials are continuing.