Caltron Maine Magnesium Salt (MARINMAG) is derived from cold water which is extracted from the salty waters of the Indian ocean and contains all the different natural forms of Magnesium including oxides, hydroxides, and carbonates facilitating better assimilation in the body. The magnesium quality depends not only on source and elemental Mg content but also on its bioavailability – that is the ability of magnesium to be absorbed and utilized by the body.