Under the outer layer of the skin is the dermis, a layer composed of specialized cells called fibroblasts and the products that they create, including collagen, elastin and hyaluronic acid. Beneath the dermis are the deeper facial fat pads which provide support to the skin and provide facial shape.
When patients are young and these tissues are healthy and full, collagen and elastin support the skin, while facial fat pads create the smooth, curved and defined facial features. Over time, as the skin loses its elasticity and fat pads are reabsorbed and shift, there is a change in facial volume and shape leading to the classic signs of aging: