Copper (Cu) is a naturally occurring metal found in soil, water, and rocks. Nutritionally, it is an essential trace mineral found in some foods and in supplements. Copper has two oxidation states (cuprous, Cu+ and cupric, Cu2+) and is involved in cell oxidation and reduction reactions. The human body contains 100 mg of Cu, with~75% of the total in skeleton and muscle tissue, whereas the remainder is found in liver, brain, blood, heart, and kidney. (Ref.1)