Zinc oxide is an inorganic compound having the formula ZnO. It is widely used in skin creams. It can prevent sunlight and ultraviolet rays from penetrating the skin and can protect skin from outside irritants. Zinc oxide is extremely effective as a sunscreen. It reflects ultraviolet rays away from the skin, providing protection against sun damage. Zinc oxide is particularly effective against long-wave UVA rays. It appears to block out the harmful rays without actually penetrating the skin.
Zinc oxide also has mild astringent and antiseptic properties, and is particularly useful for acne and wound care. Topical zinc oxide creams appear to enhance the wound healing process by delivering zinc ions to the wound and allowing them to remain there for an extended period of time.