What causes skin to become wrinkly?

Wrinkled skin is caused by a variety of biological and environmental factors such as aging, UV radiation exposure, smoking and repeated movements of certain muscles. Aging is an unavoidable process in which the fat underneath the skin diminishes and oil production is decreased, making the skin dryer and reducing elasticity.

Skin serves a variety of purposes for the body. It acts as a watertight barrier against pathogens and provides sensation through a number of nerve endings. Skin is also thermoregulatory and is able to absorb gases such as oxygen, nitrogen and carbon dioxide. The dermis and the epidermis compose the two layers of skin.