If you’ve taken melatonin before and felt like you have a hangover the next morning, or are groggy, you are likely taking too much. Many people take between 3-5mg, which is way too much and actually can signal your own brain to stop producing its own melatonin. 1mg of melatonin is all you need. So even if you think melatonin is not for you, try it again in Kikoko: it could just be that you’ve got the dose wrong.