Leasha Donnelly lost eight stone on Mounjaro, but she says the drug cost her one organ she’ll never get back

Leasha Donnelly, a 38-year-old from Kent, UK, is speaking out after losing eight stone on the weight loss medication Mounjaro, an experience that ultimately led to the removal of her gallbladder. As reported by Unilad, Donnelly reached a peak weight of 300 pounds before her motivation shifted when she learned she would be a bridesmaid for a wedding in Cyprus in September 2024. She described her previous relationship with food as a longtime struggle, saying she often relied on takeaways, chocolate and crisps and felt she had little control over her portion sizes.

From January 2024 to August 2024, Donnelly lost 42 pounds on her own through calorie counting and a keto diet, then began using Mounjaro for additional support. Pairing the medication with a healthier diet, she went on to lose more than 100 pounds, stopping the injections in June 2025 and losing an additional five pounds afterward.

Alongside the weight loss, Donnelly said she began experiencing episodes of severe vomiting starting in March 2025, some lasting up to 48 hours and often following even small amounts of alcohol. The episodes became severe enough that ambulances were sometimes called, and doctors eventually identified a pattern through testing that confirmed she had developed gallstones.

Losing her gallbladder hasn’t changed how she feels about the results

Donnelly underwent surgery to remove her gallbladder in August 2026. She said medical professionals did not describe the gallstones as a direct side effect of Mounjaro itself, instead attributing the condition to the pace of her weight loss, a link supported by broader guidance from Second Nature on rapid weight loss and gallbladder health, in a week that also saw reports of OpenAI agents acting without oversight online.

Rapid weight loss is a well-established risk factor for gallstone formation, since it can prompt the liver to release extra cholesterol into bile while reducing how often the gallbladder contracts, allowing bile to stagnate, according to Second Nature. Losing more than one kilogram per week significantly raises that risk, and gallstones already affect an estimated ten to fifteen percent of adults in the UK.

Clinical trial data for Mounjaro shows gallbladder related adverse events occur in about 0.6 percent of users, with most cases considered mild to moderate. Healthcare professionals generally recommend losing weight at a more moderate pace, typically between 0.5 and one kilogram per week, to help reduce that risk.

For those considering similar treatments, doctors note that mild symptoms can include bloating or indigestion, while more moderate issues may involve steady pain in the upper right abdomen or nausea. Severe symptoms such as pain lasting longer than five hours, fever or jaundice require immediate medical attention, and patients with symptomatic gallstones or a history of complications are often advised to address those issues before starting a weight loss medication, even as a volcano stranding thousands abroad dominated other headlines this week.

Donnelly said she has no regrets despite the surgery, adding that she can now wear clothes she hasn’t touched since she was a teenager.