What actually causes facial wrinkles?

The cells divide more slowly, and the inner layer of skin (the dermis) starts to thin. Fat cells beneath the dermis begin to atrophy (diminish). In addition, the ability of the skin to repair itself diminishes with age, so wounds are slower to heal. The thinning skin becomes vulnerable to injuries and damage. The underlying network of elastin and collagen fibers, which provides scaffolding for the surface skin layers, loosens and unravels. Skin then loses its elasticity. When pressed, it no longer springs back to its initial position but instead sags and forms furrows. The sweat- and oil-secreting glands atrophy, depriving the skin of their protective water-lipid emulsions. The skin's ability to retain moisture then diminishes and it becomes dry and scaly. Frown lines (those between the eyebrows) and crow's feet (lines that radiate from the corners of the eyes) appear to develop because of permanent small muscle contractions. Habitual facial expressions also form characteristic lines. ...  more