Magnesium is one of the most important minerals in the body, but an estimated 75% of Americans are magnesium deficient. Magnesium plays a key role in over 300 enzymatic reactions, including supporting cardiovascular, bone, muscle, energy, and neurotransmitter processes. Source Naturals magnesium is attached ("chelated") to the amino acid glycine. The magnesium bis-glycinate combination enables efficient absorption, the glycinate allowing the magnesium to transfer easily across the intestinal wall. Increased absorption means more usable magnesium for your body's needs.*