First, there are products that are left behind on the skin. These include moisturizing products designed to improve the look and feel of skin. There are also anti-aging products that promise to get rid of the sign of aging skin (e.g. wrinkles). There are sunless tanners which change the color of skin. And there are over-the-counter drug products that protect from the sun, treat skin medical conditions, treat acne, and really reduce wrinkles.