C affeine is the most widely used stimulant in the world, and one of the most common ways people consume caffeine is through coffee. About 66% of Americans drink coffee every day, so it's no shock ...

“And then, of course, tea and soft drinks tend to have less caffeine. Most people have safely under 400 milligrams a day, which is what the Food and Drug Administration considers safe,” she said.

Many mainstream energy drinks that have been on U.S. shelves for decades—like Rockstar, Red Bull, and Monster—contain roughly 10 mg of caffeine per ounce. That’s roughly on par with the ...

Many mainstream energy drinks that have been on U.S. shelves for decades—like Rockstar, Red Bull, and Monster—contain roughly 10 mg of caffeine per ounce. That’s roughly on par with the ...