Yellow Card reports record 1,176 pancreatitis cases for tirzepatide, 18 of them fatal
Reporting on the MHRA's Yellow Card data records 1,176 reports of acute and chronic pancreatitis following tirzepatide use between January 2023 and June 2026, 18 of which had a fatal outcome. For liraglutide, 137 reports were made between 2020 and 2026, one with a fatal outcome. The figures follow the MHRA's drug safety alert of 29 January 2026 which highlighted acute pancreatitis as a known but infrequent side effect that can be fatal.
What this actually means
These numbers need holding at both ends, because they get misused in both directions.
Yellow Card reports are suspicions, not confirmed cases. A report means someone thought there might be a link. It does not establish that the drug caused it. Rapid weight loss itself causes gallstones, and gallstones are a common cause of pancreatitis, so untangling the two is genuinely hard.
And they are not a rate. 1,176 reports sounds alarming until you set it against how many people are taking tirzepatide in the UK, which runs into the hundreds of thousands. The MHRA's own word for this side effect is infrequent.
What actually matters to you is the symptom, not the statistic. Severe, persistent stomach pain that may spread to your back, with nausea or vomiting, means get seen rather than wait it out. And if you suspect a side effect, report it. This data only exists because people did.
Told first, next time
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What this is. A dated, sourced note on something that changed. Peptide Register is an independent reference: it sells nothing, carries no advertising, and takes no money from any company selling any compound it covers. This is not medical advice. If a change affects a medicine you are prescribed, speak to your doctor or pharmacist rather than acting on something you read here.