Weight-Loss Jab Diarrhoea (Mounjaro®, Wegovy®, Ozempic®)
Why diarrhoea happens
GLP-1 receptor agonists such as Mounjaro® (tirzepatide), Wegovy®, and Ozempic® (semaglutide) are breakthrough weight-loss injections. But while they control appetite and help reduce body weight, they frequently trigger gastrointestinal side effects. Clinical data shows around 30–35% of patients experience diarrhoea, sometimes lasting up to 48 hours after the jab.
This happens because GLP-1 drugs slow stomach emptying and alter gut motility. They also change bile acid flow and may irritate the gut lining — resulting in loose stools, bloating, and bathroom urgency.
The lived experience
On Reddit and Facebook support groups, patients describe being “stuck at home the day after every jab” and “planning life around the toilet.” Others report fatigue, embarrassment, and anxiety about going to work or eating socially. The diarrhoea is usually not painful, but the unpredictability is debilitating.