GLP-1 receptor agonists like Wegovy and Mounjaro have transformed the weight-loss drug market, with both medications now available through the NHS for eligible patients and through private channels across the UK.
Wegovy, developed by Novo Nordisk, contains semaglutide and works by mimicking glucagon-like peptide-1, a hormone that regulates appetite and blood sugar levels. The drug signals fullness to the brain, reducing hunger and food intake. Patients typically inject it weekly, with doses escalating over time. Clinical trials show users lose roughly 15 percent of their body weight on average.
Mounjaro, produced by Eli Lilly, uses tirzepatide and targets two hormone receptors: GLP-1 and GIP. This dual-action mechanism produces stronger appetite suppression than single-receptor drugs. Users report losing up to 20 percent of body weight in trials. Like Wegovy, Mounjaro requires weekly injections.
Both drugs shift how the body processes food. They slow gastric emptying, meaning food stays in the stomach longer and creates prolonged satiety. They also influence the brain's reward pathways, making high-calorie foods less appealing.
NHS availability remains limited. Wegovy qualifies patients with a BMI of 35 or higher, or 30 with weight-related health conditions like type 2 diabetes. Mounjaro typically goes to diabetic patients first, though NHS trusts expand access gradually.
Private prescriptions cost significantly more. Wegovy runs roughly £150-200 monthly; Mounjaro similar rates. Demand far exceeds supply on both NHS and private markets.
Common side effects include nausea, vomiting, and gastrointestinal issues, particularly when dosing increases. Weight regain often occurs if users stop the medication, making these long-term commitments rather than temporary solutions.