Medication: what these drugs are and what they do
Semaglutide, sold under brand names including Ozempic and Wegovy, belongs to a class of medications called GLP-1 receptor agonists. It mimics a natural hormone released in the gut after eating. It prompts the pancreas to release insulin when blood sugar is high, suppresses the release of stored sugar from the liver, slows how quickly food leaves the stomach and acts on the appetite centres of the brain. It was used for type 2 diabetes for years before the FDA approved it for weight management in 2021.
Tirzepatide, sold as Zepbound and Mounjaro, acts on both GLP-1 and GIP receptors. It was also developed first for type 2 diabetes and was approved by the FDA for weight management in 2023.
Both are prescription medications with real side effects. Nausea, vomiting, diarrhoea and constipation are common, particularly while the dose is being increased. There are conditions in which they should not be used at all, and there are interactions with other medications. Whether either is appropriate for you is a clinical decision made after a consultation and testing, and it is reviewed as treatment goes on.
The National Institute of Diabetes and Digestive and Kidney Diseases publishes an independent overview of prescription weight management medication.