As with most other energy drinks that contain large quantities of caffeine, 5-Hour Energy can cause side effects that include insomnia, nervousness, elevated blood pressure, vomiting and rapid heartbeats. To minimize the possibility of getting these side effects, WebMD notes that manufacturer recommends consuming no more than two bottles in one day.
According to Forbes, excessive caffeine consumption can cause seizures, brain hemorrhages and heart attacks. WebMD explains that 5-Hour Energy should not be used by young children, pregnant or lactating women or those who are caffeine intolerant. In addition, the energy drink should not be used with products that contain large amounts of caffeine. These include some types of coffee and green tea. Doing so increases the possibility of developing serious side effects, according to WebMD.
5-Hour Energy is produced by Living Essentials. The energy drink was introduced into the U.S. market in 2004. As of September 2014, 5-Hour Energy is estimated to command about 75 percent of the U.S. energy drink market. Part of the products' attraction lies in its low sugar content. According to WebMD, a two-ounce bottle of artificially-sweetened 5-Hour Energy contains about four calories. In comparison, an eight-ounce bottle of sugar-free Red Bull has about ten calories, while the regular sweetened version has a whooping 100 calories. The kick in 5-hour Energy is primarily the result of its high caffeine content, not sugar.