Wrinkle

A furrow in the skin. Wrinkling is a natural feature of aging and is caused by a loss of skin elasticity. Premature deep wrinkling is usually due to overexposure to the ultraviolet rays in sunlight, and to smoking. No treatment can permanently restore skin elasticity, although some vitamin A derivatives are believed to reduce wrinkling. A face-lift smoothes out wrinkles by stretching the skin, but the effects last only about 5 years.