Energy drinks are often marketed as beverages that boost stamina, improve focus, and enhance physical output. Among dietary supplements, they rank just behind multivitamins in popularity with U.S. teenagers and young adults. Men aged 18 to 34 are the leading consumers, while nearly one in three teenagers between 12 and 17 years old report regular use of energy drinks. There are two general types of energy drinks. One is packaged like typical soft drinks, with sizes such as 16 ounces. The other