Chief among these is the use of sunscreen to protect against photoaging. The majority of the undesirable skin changes associated with aging are the result of sun exposure. The underlying collagen and elastin support of the skin breaks down because of sun exposure. This foundation of the skin also becomes more stiff and hard with age. However, collagen and elastin are only one part of a complex picture.
Young skin has more fat cells in the dermis than older skin.
This explains why older skin is more transparent. In aging the skin grows more than is necessary to cover the bones and muscles. So it sags. Gravity is not our friend in aging. Facial muscles sag too.