The first face-to-face trial of two blockbuster weight loss drugs shows that Mounjaro is more effective than rival Wegovy.

Both drugs resulted in substantial weight loss, but according to the trial, Mounjaro lost 20% of his weight, and after 72 weeks of treatment, it lost 14% of his weight.

Both drugs work, but Mounjaro may help those with the largest weight lose weight, the researchers leading the trial said.

Both drugs induce the brain to make you feel full and make you eat less, but instead burn the fat stored in the body, but their subtle differences in how they work to explain the difference in effectiveness.

Wegovy, also known as Semaglutide, releases hormones released by the body after a meal to flip an appetite switch in the brain. Mounjaro or Tirzepatide flips two.

The trial was paid by Eli Lilly, a manufacturer of Mounjaro, and involved 750 obese people with an average weight of 113 kg (nearly 18 stones).

They were asked to take the highest dose that could tolerate one of two drugs.

These findings were presented at the European Obesity Conference in Malaga and the New England Journal of Medicine:

• 32% lost a quarter of their weight on Mounjaro, compared to 16% of Wegovy
• Those on Mounjaro lost 18 cm from their waistline on average, while those on Wegovy were 13 cm.
• People on Mounjaro have better blood pressure, blood sugar and cholesterol levels.
• Both have similar levels of side effects.
• Women tend to lose more weight than men.

"Most obese people perform well with semaglatide (Wegovy) and the high-end people may end up doing better with tirzepatide (Mounjaro)" said Dr. Louis Aronne, who conducted a trial at Weill Cornell Medicine's Comprehensive Weight Control Center in New York.

In the UK, both drugs are available from professional weight management services but can also be purchased privately.

Professor Naveed Sattar from the University of Glasgow said the drugs are "a good choice" for patients, but "many people will be satisfied with 15% weight loss...many people want to lose as much weight as possible".

He added: "In the UK, Tirzepatide's sales private is now ahead of Semaglutide, which is just a reality - this paper I imagined will accelerate."

However, Wegovy has also obtained permission for other diseases, such as preventing heart attacks, and the equivalent trial in Mounjaro has not been completed.

A large number of studies on weight loss medications are still underway. Higher doses of current drugs are being tested, as well as new approaches to adopt them, such as oral pills and new drugs that act in different ways on the body, and are under investigation.

This means that the final championship in the field has not been determined yet.

Professor Satar said the number of studies conducted means we may be approaching the point where “preventing obesity may also be possible soon”, but thinks “it would be better to make our society healthier to prevent people from becoming obese.”