More than 200 deaths have now been reported to UK medicines regulators as being suspected of being linked to popular weight-loss injections, according to the latest figures from the Medicines and Healthcare products Regulatory Agency (MHRA).
The reports, submitted through the MHRA’s Yellow Card Scheme, include 120 deaths associated with tirzepatide, marketed as Mounjaro, making it the medicine with the highest number of suspected fatal reports among the new generation of weight-loss drugs.
The latest data also show that more than 106,000 suspected adverse reactions have been reported in connection with Mounjaro. Many involve gastrointestinal problems such as nausea, vomiting and diarrhoea, although the reports cover a wide range of medical issues.
Semaglutide, the active ingredient in Wegovy and the diabetes medications Ozempic and Rybelsus, has been linked to 48,089 suspected adverse reactions and 59 reported deaths. Meanwhile, liraglutide, sold as Saxenda for weight management, has been associated with 4,491 suspected adverse reactions and 37 reported deaths.
Taken together, the three medications have generated more than 158,000 reports of suspected side effects and 216 reports of deaths submitted to the MHRA.
However, the regulator has stressed that these figures should not be interpreted as evidence that the medicines caused the deaths or illnesses. The Yellow Card Scheme is designed as an early warning system that allows healthcare professionals, patients and carers to report any suspected adverse reaction following the use of a medicine. A report simply records that someone suspected there may have been a link.
An MHRA spokesperson urged caution when interpreting the statistics, noting that millions of prescriptions for GLP-1 medicines have now been issued across the UK.
“It is important to place these reports in the context of the millions of GLP-1 prescriptions issued in the UK,” the spokesperson said.
The regulator added that reporting rates can increase as more people begin using a medicine and as awareness of potential side effects grows.
The MHRA said it continuously monitors the safety of GLP-1 receptor agonists by reviewing Yellow Card reports alongside clinical studies, scientific publications and international safety data. If new risks emerge, updated guidance would be issued promptly to healthcare professionals and patients.
Based on the evidence currently available, the agency maintains that the benefits of these medicines continue to outweigh their risks when prescribed and used according to their licensed indications.
The drugs have become increasingly popular in recent years, not only for treating type 2 diabetes but also as highly effective treatments for obesity. Clinical trials have demonstrated significant weight loss in many patients, reducing the risk of diabetes, heart disease and other obesity-related conditions.
Health Secretary Yvette Cooper also sought to reassure the public that robust monitoring systems remain in place.
She said the NHS allows safety reports from across the country to be collected and analysed centrally, enabling regulators to identify emerging concerns quickly. She added that expert regulators continually assess all available evidence and ensure that any significant safety issues are communicated to ministers, healthcare professionals and the public.
While the latest figures may understandably concern patients, health experts emphasise that suspected reports are not proof of causation. Nevertheless, the growing number of Yellow Card submissions highlights the importance of ongoing surveillance as these medicines continue to be prescribed to increasing numbers of people across the UK.
