Poker- someone would not take 1200mg calcium and 400mg of magnesium if they are constipated. This dose would constipate them even more. Calcium supps are not the best idea when someones digestion is off. First of all calcium supps are hard to digest, and second calcium can buffer important digestive acids and cause digestion to be even worst. Eating a balance diet and staying away from acidic man-made preservatives is much more important than calcium supps.