Like all medicines, Wegovy® can cause side effects, including nausea, vomiting, constipation and diarrhoea. Not everybody experiences them, but if you do, they usually settle after a few weeks once you get used to the medication. One of the reasons for the gradual increase in medication every few weeks is to give your body the chance to tolerate the medication so that these side effects are less likely to happen or be less problematic.