The ingredients in Rockstar energy drinks are: high fructose corn syrup, taurine, carbonated water, citric acid, dextrose, guarana seed extract, natural and artificial flavors, caramel color, ascorbic acid, sodium benzoate, caffeine, potassium sorbate, inositol, niacinamide, l-carnitine, ginkgo biloba leaf extract, milk thistle extract, calcium pantothenate, cyanocobalamin, Siberian ginseng root extract, pyridoxine hydrochloride and riboflavin. Depending on the flavor, the drink can contain 80 to 229 mg of caffeine per serving.
The main active ingredient for Rockstar energy drinks is caffeine. The safe limit of caffeine consumption for healthy adults is up to 400 mg per day, according to WebMD. It should be noted that this limit varies depending on the individual, as the safe limit for pregnant women is up to 200 mg per day.
High doses of caffeine can prove to be dangerous, with side effects including insomnia, unstable heart rhythms, seizures and other problems, reports WebMD. It is also important to note that energy drinks are classified as dietary supplements, which are not subject to the same regulations and evaluations as foods are by the U.S. Food and Drug Administration. A health care provider should be consulted with any questions about medical conditions prior to consuming energy drinks, advises the FDA.