UK regulatory data from the MHRA Yellow Card Scheme reveals that over 200 deaths and 150,000 adverse reactions have been reported with suspected links to weight loss drugs like Mounjaro and Wegovy. Annual suspected fatalities rose 300% between 2024 and 2025. While severe gastrointestinal complications like bowel perforations have led to high-profile deaths, including Caroline Savage and Susan McGowan, regulators and manufacturers emphasize that reports show suspicion rather than proven causation, maintaining that the drugs' benefits outweigh their risks.
Weight loss drug death reports
- ▪The Medicines and Healthcare Products Regulatory Agency recorded 120 suspected deaths linked to tirzepatide, sold under the brand name Mounjaro, since its licensing in 2024
- ▪Data from the UK Medicines and Healthcare Products Regulatory Agency Yellow Card Scheme shows that more than 200 deaths have been reported with suspected links to weight loss drugs, including Mounjaro and Wegovy
- ▪The Medicines and Healthcare Products Regulatory Agency recorded 59 suspected deaths linked to semaglutide, the active ingredient in Wegovy and Ozempic, and 37 suspected deaths linked to liraglutide, sold as Saxenda
Adverse reaction reporting trends
- ▪Annual suspected deaths linked to weight loss injections in the UK rose by 300 percent between 2024 and 2025, increasing from 22 to 94 fatalities
- ▪More than 150,000 adverse reactions have been reported in the UK in connection with weight loss drugs since 2010, with 18,000 of those reactions classified as serious or fatal
- ▪A University College London study estimated that 1.6 million people in England, Wales, and Scotland used weight loss drugs between early 2024 and 2025, with an additional 3.3 million planning to use them in the near future
Gastrointestinal complications
- ▪A UK inquest heard that 73-year-old Caroline Savage died of faecal peritonitis caused by a hole in her bowel after increasing her dose of the weight loss drug Mounjaro
- ▪Susan McGowan, a 58-year-old nurse, died in September 2024 from organ failure, septic shock, and pancreatitis, with the prescribed use of tirzepatide listed as a contributing factor on her death certificate
- ▪Weight loss injections can cause the gut to work slowly, which may trigger a back-up of waste products that increases pressure in the intestines and raises the risk of a bowel perforation
MHRA Yellow Card system
- ▪The Medicines and Healthcare Products Regulatory Agency Yellow Card Scheme allows patients, relatives, and healthcare professionals to report suspected side effects, but these reports do not prove the medicine caused the reaction
- ▪The Medicines and Healthcare Products Regulatory Agency stated that reporting volumes for weight loss drugs can be influenced by increased clinical use and greater public awareness of potential side effects
Regulatory safety monitoring
- ▪The Medicines and Healthcare Products Regulatory Agency stated that, based on current evidence, the benefits of GLP-1 receptor agonists outweigh their potential risks when used in line with authorized uses
- ▪UK Health Secretary Yvette Cooper stated that the National Health Service allows safety experts to continuously monitor and analyze adverse reaction reports to ensure public safety
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