We recommend sticking with the same type of weight loss injection, meaning the same active ingredient. However, if you wish to switch, you should start with the lowest dose of the new medication. A person who was previously prescribed Wegovy® should always start with a 2.5 mg dose of Mounjaro®. There is no "washout period" required: there is no time needed to clear the medication from the body before starting a new treatment. You can easily continue with the new treatment the following week.