Facial aging is due to a combination of changes to the skin and changes to the facial bones supporting the skin.
Collagen loss is a key factor in aging
As skin ages, the dermis thins due to collagen loss, thus reducing its ability to retain elasticity (from elastin) and moisture (from hyaluronic acid). In addition, facial fat moves and resettles, changing the facial structure. While these changes are occurring in the
dermis and subcutaneous layers of your skin as it ages, the epidermis changes color and texture.
Over time, bone is reabsorbed, becoming thinner and more brittle. This causes your face to appear thinner and results in a weaker-looking jaw. Osteoporosis can compound these effects, as the bones thin faster.
Due to a combination of factors, skin texture and color also change. The skin becomes rougher and drier, and blemishes and discolorations appear. They appear first as light blemishes and changes in pigmentation. Later, raised spots of pigmentation may appear along with continued discoloration. Skin also increases in redness. Veins become lightly visible, becoming more visible with advanced aging.
Collagen loss leads to loss of elasticity and moisture
The loss of collagen results in the loss of elastin and hyaluronic acid, as they need collagen to provide the structure for their retention. This reduces the moisture, suppleness, and elasticity of the skin, and causes thinning in the face, called volume loss.
The face also thins due to fat loss, as well as the movement of fat to other areas of the face. Skin appears looser and sags. The diminished elasticity of the skin reduces its ability to retain its shape and it does not conform as closely to the contours of the face. Gravity then pulls on both the skin and the underlying fat, and they move down your face. This results in sagging eyelids, bags under the eyes, and jowls.