Sisu Ester-C Energy Boost - Orange Flavour - Each convenient ‘to-go’ package contains 1,000 mg of Ester-C per serving. In addition to vitamin C, there are multiple nutrients that the body needs every day to function at its best, including B vitamins and minerals. Electrolytes such as sodium, calcium, and magnesium are minerals essential for rehydration and energy production as well as cardiovascular, muscle, and nervous system functions. Ester-C Energy Boost combines all of these important nutrients in a convenient drink mix to help keep active, busy people feeling their best and performing at their peak. Take it to work, the gym, or use at home.