A daily pill could help people keep weight off and stop them needing other long-term medications, scientists behind landmark new trial data have suggested.

The researchers said orforglipron could help prevent more than 200 diseases associated with obesity and could be prescribed to prevent lower levels of overweight tipping into obesity.

A large-scale randomised controlled trial found that patients using injectable GLP1s could maintain most of their weight loss if they switched to far cheaper daily pills.

About 30% of adults in the UK are living with obesity, with those on Wegovy or Mounjaro taking about seven medications for other health conditions.

The trial, presented at the European Congress on Obesity 2026 in Istanbul and published in Nature Medicine, studied to what extent switching from weekly GLP1 jabs to taking daily orforglipron tablets caused patients to regain their lost weight.

Previous studies have shown people prescribed semaglutide or tirzepatide injections typically lose 15-20% of their body weight, but most patients regained two-thirds of the weight they had lost within a year of coming off the jabs.

The new trial, funded by Eli Lilly, which manufactures Mounjaro, found that participants who switched to orforglipron pills were able to keep far more of that weight off than those given a placebo.

Researchers followed 376 US patients who had been on tirzepatide (sold as Mounjaro in the UK) and semaglutide (Wegovy) jabs for 72 weeks, who then took orforglipron or a placebo for a year.

They found that after a year, those on tirzepatide kept almost 75% of that weight off after switching to the daily pill, compared with 49% for those given placebo.

For semaglutide, patients maintained almost 80% of the previous weight lost, compared with 38% of those on placebo.

Swapping to the tablets also meant that improvements in patients’ blood pressure, cholesterol and blood sugar levels were maintained, the authors observed.

Dr Louis Aronne, director of the Comprehensive Weight Control Center at Weill Cornell Medicine, said the findings showed obesity should increasingly be treated like other chronic diseases.

“The beauty of treating obesity is you are treating all of these things: you treat the glucose, treat the lipids, treat the blood pressure, all by treating the obesity,” he said.

If obesity were treated effectively, there would be no need to treat the other cardio-metabolic risk factors, Aronne added.

“The average patient that we see in our clinics … the average BMI is 38, the average person is on seven medications and has sleep apnoea.

“What would happen if you started treating people with a BMI of 25 or 27 and they never got to [severe obesity]?

“I think that is very appealing model to me but it has to be proved.”

Reacting to the findings, Dr Marie Spreckley, research programme manager at the University of Cambridge, said: “Many people do not want to remain on injectable therapy indefinitely due to treatment burden, convenience, travel, storage requirements, cost or personal preference.

“The possibility of transitioning to an oral therapy while maintaining a substantial proportion of the previously achieved weight reduction could therefore represent an important additional option within longer-term obesity care pathways.”

Dr Simon Cork, senior lecturer in physiology at Anglia Ruskin University, said that while patients lost more weight using injectable drugs, they are expensive.

“This limits their long-term applicability both for private purchasers and the NHS,” he said.

“Newer, oral medications are significantly cheaper to manufacture, but do not tend to produce the same level of weight loss seen with injectable medications.”

While more research was needed, he added that the findings point to “a potential future for how patients with obesity are treated, and how the success of weight loss can be maintained”.