GLP-1-based drugs such as semaglutide (Wegovy) and tirzepatide (Mounjaro) work by helping people to feel less hungry. This results in them eating less – leading to weight loss.

Studies show that these drugs are very effective in helping people lose weight. In clinical trials of people with obesity, these drugs lead to a weight loss of up to 20% body weight in some instances.

But it’s important to note that not all the weight lost is fat. Research shows that up to one-third of this weight loss is so-called “non-fat mass” – this includes muscle and bone mass.