I've just started using Mounjaro after a 3 week break from Wegovy. How long before I can expect my appetite to decrease after my first dose? I did my first injection mid afternoon yesterday (Friday) and so far, have not noticed any difference. When I was on Wegovy and prior to that,Ozempic,I noticed a decrease in my appetite after 12 hours (mainly due to feeling slightly nauseous!). Everything I've looked at online gives different opinions. Some say I'll notice a difference within 12 - 24 hours,others say it could take 2 - 3 weeks.