Monster Energy. Though it is not widely advertised in the media, Monster receives a large amount of recognition from its sponsorship of various sporting events. The caffine content of most Monster energy drinks is approx. 10mg/oz(33.81mg/100mls), or 160 mg for a 16 oz can. As with most other energy drinks the packaging usually has a warning printed on it saying to limit the number of cans consumed in a day - to 3 for the 16 oz size (one per day in Australia and the UK), and it is not recommended for children, pregnant women or people sensitive to caffeine.