If you drink coffee in order to feel refreshed, you need to choose the right time. You can determine the time by the cortisol level in the body. Most people have a high cortisol level between 8 AM and 9 AM, the next peak is between 12 AM and 1 PM; and the last one is from 5:30 PM — 6:30 PM. It’s better to drink coffee after you start feeling tired. After the last peak, it’s not recommended to drink coffee again if you want to be able to fall asleep that night.