Each capsule provides 170 mg of Calcium and 94 mg of Magnesium from dolomitic lime.  It supports the heart by reducing the amounts of excess ureas i.e. the undigested protein within they system.  Excess ureas/undigested protein causes the heart beat harder than it should, if you experience fatigue and can hear your own heartbeat you need Heart Support.  One should know the levels of their ureas before using this product, for low ureas are just as dangerous as excess ureas!