Zinc is an essential mineral with a wide variety of functions within the human body. Zinc is a component of over 300 enzymes needed to repair wounds, maintain fertility in adults and growth in children, synthesize protein, help cells reproduce, preserve vision, boost immunity, and protect against free radicals, among other functions.

In some trials, zinc lozenges have reduced the duration of colds in adults, though they have not been demonstrated to be effective in children. The ability of zinc to shorten colds may be due to a direct, localized anti-viral action in the throat. A small, preliminary trial has also shown zinc sulfate to be effective for contact dermatitis, a skin rash caused by contact with an allergen or irritant.

Zinc can reduce the body’s ability to utilize copper, another essential mineral. The ability to interfere with copper makes zinc an important therapy for people with Wilson’s disease, a genetic condition that causes copper overload. In healthy individuals, however, this effect is best offset by Copper supplementation.