Once dismissed as a Cinderella subject, obesity treatment has been transformed by a new class of appetite-suppressing drugs such as Ozempic and Wegovy. At the European Congress on Obesity (ECO) in Málaga this week, researchers presented evidence that these medications offer health benefits that go far beyond weight management, prompting one expert to describe the developments as an 'extraordinary week' for the field.
The drugs work by mimicking a hormone called GLP-1, which is released in the gut after eating and acts on receptors throughout the body, including the brain. Novo Nordisk's semaglutide, the active ingredient in Ozempic and Wegovy, was originally developed to lower blood sugar in diabetes but quickly showed dramatic effects on weight. Eli Lilly's rival drug Mounjaro, containing tirzepatide, mimics GLP-1 as well as a second hormone and produced even more impressive results in the first head-to-head trial, with participants losing an average of 20% of their body weight after 72 weeks.
Beyond weight loss, a study published in January suggested these jabs could reduce the risk of 42 diseases, including heart disease, cancer, clotting disorders, Alzheimer's, chronic kidney disease, addiction and psychiatric conditions. A phase 3 trial of semaglutide in patients with fatty liver disease, or MASH, found the drug could halt and even reverse the condition, which affects one in five UK adults. Prof Philip Newsome of King's College London, who presented the findings, said the benefits to the liver appeared partly independent of weight loss, which he described as 'quite interesting and exciting'.
Another trial indicated that the drugs could almost halve the risk of obesity-related cancers, with a larger effect than would be expected from weight loss alone. Two further studies suggested potential mental health benefits. Dr Toby Pillinger, a psychiatrist at King's College London, noted that the drugs appear to act on the brain's reward system, raising the possibility of direct neurological effects. 'They've been likened to the Swiss army knife of medicines,' he said, adding that researchers are only beginning to understand their effects on brain function.
Pillinger envisages a similar revolution in psychiatry, with addiction, binge-eating disorders and schizophrenia as obvious targets for future trials. However, questions remain about whether the benefits extend beyond those of achieving a healthy weight, as Prof Susan Jebb of the University of Oxford pointed out. There is also concern about what happens when patients stop taking the medication, as data on long-term outcomes is patchy because pharmaceutical companies typically stop tracking people once they discontinue treatment.
