Susan McGowan had worked as a bed manager at University Hospital Monklands in Airdrie for more than thirty years before she decided to try a new weight-loss injection that colleagues were beginning to talk about. She took two low-dose injections of tirzepatide, sold under the brand name Mounjaro, over about two weeks before her death on 4 September 2024. Her death certificate, seen by the BBC, listed multiple organ failure, septic shock and pancreatitis as the immediate cause of death, with the use of prescribed tirzepatide recorded as a contributing factor. It was, at the time, thought to be the first death in the UK officially linked to the drug.
Eighteen months on, that single case has become a data point in a far larger picture. Weight loss jabs including Mounjaro and Wegovy have now been linked to at least 216 deaths in the UK, with annual fatalities rising by 300 per cent between 2024 and 2025, from 22 to 94. Since tirzepatide was licensed in 2024, 120 deaths linked to the drug have been reported to the MHRA, with 59 associated with semaglutide, the active ingredient in Wegovy and Ozempic, and 37 with liraglutide, sold as Saxenda. A further death was linked to retatrutide, a drug not approved for use in the UK and likely to have been bought on the black market.
The fatalities sit within a much wider volume of reporting. Since the earliest recorded figure in 2010, a total of 150,000 adverse reactions have been associated with these drugs, including 18,000 classed as serious or fatal. Of those 18,000 serious reports, 11,500 concern tirzepatide specifically, with close to 8,000 involving women. Many of the reported side effects involve the gastrointestinal system, including pancreatitis and gastroparesis, a condition sometimes described as stomach paralysis.
None of this establishes that the drugs caused these deaths. Yellow Card is a spontaneous reporting system, designed to flag suspicion rather than confirm causation, and patients taking GLP-1 medicines for weight loss or diabetes frequently carry other conditions, including cardiovascular disease and gallstones, that independently raise mortality risk. An MHRA spokesman said it was important to place the reports in the context of the millions of GLP-1 prescriptions issued in the UK, noting that reporting volumes can be influenced by increased use and greater public awareness of potential adverse reactions. The regulator maintains that the benefits of these medicines continue to outweigh the risks when used as licensed.
The figures nonetheless emerged in the same fortnight that an inquest heard how a 73-year-old grandmother, Caroline Savage, died after increasing her dose of Mounjaro, and they have prompted the MHRA to refer the full set of UK fatality reports to an expert group within the Commission on Human Medicines for review
What makes the picture harder to police is where these prescriptions are coming from. An estimated 1.6 million adults in Great Britain used weight-loss drugs between early 2024 and early 2025, according to research from University College London. Studies suggest around 40 per cent of users obtain the drugs online without a prescription, with others sourced informally from family or friends, and complaints to the Advertising Standards Authority about unsupervised online sales rose from 124 in 2023 to 492 in 2025. Ms McGowan bought her prescription through a registered online pharmacy rather than a black-market seller, which underlines that the safety questions extend beyond illicit supply into the regulated private market as well.
For NHS prescribers, who now offer tirzepatide through specialist weight management services, and for the private clinics and online platforms that account for the bulk of current usage, the rising toll sharpens a question that has so far been answered mainly with reassurance. The drugs remain licensed, the benefits are judged to outweigh the risks in aggregate, and demand shows no sign of slowing. Whether the monitoring system built to catch early warning signs can keep pace with a patient population now numbering in the millions is a separate matter, and one the Commission on Human Medicines will need to settle before the death count climbs further.
