Weight-loss injections such as Ozempic and Mounjaro may outperform metformin in preventing diabetes, major analysis suggests

Weight-loss injections such as Ozempic and Mounjaro may be more effective than diabetes medicines at preventing the condition, a study suggests.

Researchers found that people given GLP-1 injections had a 31% lower risk of developing type 2 diabetes than those taking metformin, the standard treatment for the disease.

They were also 41% less likely to die from any cause and had lower rates of heart attack, stroke and heart failure.

Experts said the results raise the possibility that the drugs, which are already used to treat type 2 diabetes and obesity, could also be used to help prevent the illness.

“The great news with prediabetes is that it’s still possible to reverse the progression of the disease,” said study author Dr Vinicius de Sousa Barzon Serra, a research fellow in the department of cardiovascular medicine at the Mayo Clinic in Arizona.

“This research may add to the case for considering GLP-1 medications earlier for certain patients, rather than waiting until they develop type 2 diabetes.”

Prediabetes affects one in 12 Britons and refers to blood sugar levels that are above normal but not yet high enough for a diagnosis of type 2 diabetes.

The study reviewed medical records for more than 250,000 adults with obesity and prediabetes.

Half of the patients were taking medicines including semaglutide, the ingredient used in Ozempic and Wegovy, and tirzepatide, which is found in Mounjaro.

The rest were taking metformin, the most commonly prescribed diabetes medicine in the UK.

Of the 4.2 million people diagnosed with type 2 diabetes in Britain, three million take metformin.

The drug is usually given to people who already have a diabetes diagnosis, although it is sometimes used off-label to try to prevent the disease.

But the new findings suggest weight-loss injections may do a better job than metformin at slowing the progression of diabetes.

Compared with patients on metformin, those using the injections were 50% more likely to bring their blood sugar back to normal, sharply reducing the chance of progressing to full type 2 diabetes.

They also experienced 25% fewer cases of heart failure, 20% fewer strokes and 15% fewer heart attacks.

Cases of atrial fibrillation, a heart rhythm disorder that can raise the risk of stroke, were also 8% lower.

Experts believe much of the benefit may come from the substantial weight loss caused by the drugs, which can improve the body's sensitivity to insulin and help return blood sugar to healthier levels.

Dr Serra said metformin remains a first-line treatment and is far cheaper than the injections, which can cost patients up to £300 a month.

“This is less about replacing one medication with another and more about discussing additional options with specific patients,” he added.

Robert Eckel, a past volunteer president of the American Heart Association who was not involved in the study, said weight-loss injections “provide another option for prevention”.

The research is due to be presented at the American Heart Association’s Scientific Sessions 2026, but it has not yet been peer-reviewed or published in a scientific journal.

Because the findings come from medical records rather than a clinical trial, the researchers warned that the study cannot prove the drugs directly caused the benefits observed.