Clinical trial in Ireland challenges beliefs about Ozempic and similar new obesity treatments

A study conducted at St. Vincent's University Hospital (SVUH) in Dublin challenges the assumption that weight loss drugs such as Ozempic, Wegovy or Monjaro work only by promoting a feeling of satiety and making people eat less.

The randomised controlled trial with 30 patients was led by Professor Donal O'Shea, SVUH and UCD School of Medicine, and investigated the family of drugs based on the hormone glucagon-like peptide-1 (GLP-1).

The today in Journal of the Obesity Societyshow that there is a strong correlation between the increase in metabolic activity caused by once-daily GLP-1 treatment and the amount of weight lost. In addition, people with low metabolic activity before starting treatment benefited the most.

Professor O'Shea said: “This study challenges the conventional wisdom about these newer treatments that they simply make you eat less and that the effect on energy expenditure is minimal. Given the relatively small number of people studied, the strength of this association is surprising and suggests that this increase in metabolic activity is a significant contributor to the effects of these drugs.

“Safe medical treatment of obesity is still in its infancy and we need to understand exactly how the treatment works. Understanding how these agents increase energy expenditure should be an important part of future research.

“It always seemed too simplistic to me that these new treatments just make people eat less. So the result of this study is an exciting advance in our understanding of how these new anti-obesity drugs work. The results also provide scientific evidence that treating obesity is not simply about eating less and exercising more – that's the prevention part – but that the treatment is more complex.”

The 30 patients underwent special imaging of abdominal fat using a PET-CT scanner; the scans were taken before and after six months of treatment with GLP-1.

Co-author of the study was Professor Silke Ryan, SVUH.