Caffeine

Technically, a drug is a chemical substance used to prevent or cure disease or to enhance a person's physical or mental welfare. In fact, people use caffeine for all of these purposes and caffeine can do all of these things, but usually in a very limited way. The actual source of caffeine is the coffee bean, tea leaf, kola nut and cacao pod. When isolated in pure form, caffeine is a white crystalline powder that …

…cup of coffee with 200 mg of caffeine and 6 hours later about 100 mg of that caffeine is still in your system. You may be able to fall asleep, but your body probably will miss out on the benefits of a deep sleep. That deficit adds up quickly and the next day you feel worse, so caffeine is needed first thing the morning. This cycle continues day after day, which is why 90% of Americans consume caffeine daily.