Caffeine and Your Brain – NIH

A hot cup of coffee or tea is a highlight of the morning for some people. It can make you feel awake and alert. Caffeine is the chemical that causes these sensations. But does caffeine have other effects on the brain?

Caffeine is found naturally in tea and coffee. But it is added to energy drinks and many types of soda. It’s even put in some snack foods and medications. More than eight out of 10 adults in the U.S. consume caffeine in some form.

So how does caffeine wake you up? Your body naturally produces a chemical called adenosine. It builds up in your body during the day.