GLP-1 receptor agonists like Wegovy and Mounjaro have fundamentally reshaped the weight-loss medication landscape, with both drugs now accessible to eligible NHS patients and private buyers in the UK.

Wegovy, semaglutide manufactured by Novo Nordisk, and Mounjaro, tirzepatide from Eli Lilly, work by mimicking hormones that regulate appetite and blood sugar. Semaglutide targets GLP-1 receptors in the brain and gut, signaling fullness and reducing hunger drive. Tirzepatide operates as a dual agonist, hitting both GLP-1 and GIP receptors for amplified appetite suppression.

Both drugs slow gastric emptying, meaning food moves through the digestive system more gradually. This extends satiety and prevents rapid blood sugar spikes. Patients typically report eating significantly less without conscious restriction, a distinction from older weight-loss medications that relied on stimulant effects.

Clinical data shows Mounjaro delivers steeper weight reduction than Wegovy in head-to-head comparisons. Tirzepatide patients averaged 22 percent body weight loss in trials, versus 17 percent for semaglutide users. Eli Lilly has since captured market momentum, with Mounjaro prescriptions surging as patients and physicians recognize the advantage.

NHS availability remains restricted to specific criteria, typically type 2 diabetes patients or those with obesity-related complications. Private clinics have loosened gatekeeping, fueling demand and shortages. Supply constraints initially limited access, though production has ramped significantly.

Side effects include nausea, vomiting, and gastrointestinal distress, particularly at dose initiation. These typically subside as bodies adjust. Appetite rebound follows discontinuation for most users, making long-term pharmaceutical management the realistic expectation rather than permanent lifestyle shifts.

The drugs' popularity stems from efficacy unmatched by previous options. They've moved beyond diabetes treatment into mainstream obesity management, reshaping pharmaceutical economics and how the UK