From youth playing fields to major-league clubhouses, caffeinated energy drinks such as Red Bull and its scores of cousins have become a familiar presence in sports…In the U.S., cola-type drinks are limited by the FDA to 71 milligrams of caffeine per 12-ounce serving. But no such limit applies to energy drinks marketed as dietary supplements, and manufacturers are not required to list the caffeine content or all ingredients on the label, sometimes opting for the term "energy blend" or "proprietary blend. …"They regulate a can of cola," said John P. Higgins, a sports cardiologist at the University of Texas Health Science Center at Houston and co-author of a 2010 article on energy drinks published in the Mayo Clinic Proceedings. "These are like a free-for-all."
Arizona Republic, by Robyn Norwood,
Additional coverage: USA Today