This is an excellent calcium supplement that actually tastes good. It's an antacid, but I use it as a calcium supplement for a very special reason. I become calcium depleted when I donate plasma. I lose the electrolytes in the donation, plus the citrate anticoagulant used at the plasma center binds calcium. The result often leads to extremely painful muscle cramps due to my blood calcium level becoming too low. This supplement remedies that right away while managing to taste good, and not like chalk. Effectiveness It stops calcium depletion cramps right away. I couldn't ask for better. Once, in the plasma center, I developed jaw cramping. They stock this remedy, knowing that this commonly happens to donors, and they gave me three tablets, and the pain went away. Ease of Use I simply chew two tablets by themselves. I don't have to take them with anything else or at any certain time other than when needed. Immediacy Within seconds, the cramps subside. I get foot and calf cramps so intense that it makes me want to yell. This fast relief is a godsend.