What is Mounjaro and how does it work for weight loss?
Mounjaro is the brand name for tirzepatide, a once-weekly injection that acts on two natural “incretin” hormones — GLP-1 and GIP — to help regulate appetite and blood sugar, supporting weight loss. It mainly works by reducing hunger signals in the brain and slowing how quickly the stomach empties, helping you feel full sooner and for longer so you tend to eat fewer calories. By mimicking GLP-1 and GIP, it also helps the body release insulin appropriately and reduce glucagon, stabilising blood sugar and further supporting weight management. In the UK, tirzepatide is used alongside lifestyle measures (a reduced-calorie diet and increased physical activity) within structured weight-management services.
- Dual-action incretin therapy: tirzepatide activates both GLP-1 and GIP receptors to target appetite and metabolism.
- Reduces hunger and slows gastric emptying, increasing feelings of fullness to lower calorie intake.
- Supports blood-sugar control by boosting insulin release when needed and suppressing glucagon.
- Once-weekly subcutaneous injection taken on the same day each week.
- Used with lifestyle support in UK specialist weight-management pathways.