Celsius is not recommended for people sensitive to caffeine, children under the age of 12, or women that are pregnant or nursing. . Celsius contains 200mg of caffeine which is similar to drinking two cups of coffee over a 3 hour period. Results may vary among individuals. For people that regularly consume caffeinated beverages, Celsius is a great tasting way to replace the existing forms of caffeine – calorie filled sodas, energy drinks, and sugary coffees.