The basic line is that energy drinks should never be consumed by children or teenagers. Sports beverages provide just a limited use for pediatric athletes. They can be mixed together but the colorings in many brands are not compatible with each other or with soda pop. The most popular energy drinks in the United States are Red Bull, Rockstar, Amp, and Full Throttle. All of these products contain caffeine as well as taurine, glucuronolactone, and B-complex vitamins. Although they all share these five ingredients, they differ from one another in their flavor profiles and concentrations of other substances within them. For example, Rockstar has more sugar than other brands while Full Throttle is less sweet. The amount of caffeine in an energy drink varies depending on how it is made. Some brands contain less than 100 milligrams of caffeine per 12 oz beverage while others have up to 400 mg. The actual amount you consume will determine how you feel later on. Caffeine is a stimulant that can increase your heart rate and blood pressure at high doses. It can also cause irritability, anxiety, headaches, and insomnia at lower doses. People between the ages of 18 and 24 account for a large percentage of emergency room visits due to energy drink consumption.