Key facts
- NHS spending on Mounjaro has quadrupled in one year.
- Total spending on the drug now exceeds £500 million.
- Prescriptions rose from 1.1 million to 3.1 million.
- The period for this increase was between the 2024/25 and 2025/26 financial years.
Spending by the UK's National Health Service (NHS) on the weight loss jab Mounjaro, also known as tirzepatide, has quadrupled over the past year, reaching more than £500 million. This surge in expenditure makes it the most expensive drug for the NHS. The number of prescriptions for Mounjaro increased significantly from 1.1 million in the 2024/25 financial year to 3.1 million in the 2025/26 financial year. The drug is sometimes referred to as the 'King Kong' of weight loss jabs due to its potency.