Drug maker Novo Nordisk says semaglutide, the active ingredient for the weight loss jab Wegovy, does not slow Alzheimer's - despite initial hopes that it might help against dementia.
Researchers began two large trials involving more than 3,800 people after reports the medicine was having an impact in the real world.
But the studies showed the GLP-1 drug, which is already used to manage type 2 diabetes and obesity, made no difference compared to a dummy drug.
The disappointing results are due to be presented at an Alzheimer's disease conference next month and are yet to be published in a peer-reviewed journal.
Dr Susan Kohlhaas from Alzheimer's Research UK said the results would come as a blow for people affected by Alzheimer's.
