Caffeine in an energy drink can equal 15 Cokes, studies say

While names like AMP Energy, Pepsi Max, Red Bull and Rockstar can sound exciting, that hyped-up feeling isn't from just the name -- one energy drink can pack as much caffeine as downing 15 cans of Coca-Cola, researchers say.

Researchers looked at energy drink ingredients, including caffeine, guarana, ginseng, taurine and sugars, and concluded that better performance can be attributed to the energy drinks' caffeine content. Two studies looked at energy drinks and their use by teenagers and athletes and have been published in the medical journal The Physician and Sportsmedicine.