The common ingredients usually include sugar (8.4 fl oz of Red Bull contains 27g of sugar. There are 54g of sugar in 16oz Monster energy drinks, according to MyFitnessPal), caffeine or guarana, amino acids, and herbal supplements. The amount of caffeine itself in energy drinks can be extremely hazardous to your health. It can lead to insomnia, headaches, anxiety, restlessness, nervousness, nausea, and irritability.