If there is such thing as a fountain of youth, it surely contains a fix for lost skin elasticity. Along with gray hair and a penchant for the good old days, loss of elasticity in skin is a telltale sign of advanced age. It is mainly caused by a loss of collagen and elastin, which in turn leads to wrinkles [source: Lee]. Skin sags over time, too. This is due in part to loss of elasticity, but also to the natural pull of gravity on the skin over the course of a lifetime. As we get older, the epidermis loses lipids (fatty substances) that keep skin moisturized, further contributing to the wrinkle problem [source: American Academy of Dermatology]. Skin becomes thinner as we age - almost transparent in some cases - and loses a lot of the underlying fat layer that keeps young skin smooth and supple. Older people also experience a loss of oil and sweat glands over time, which contributes to dry skin and makes it harder for them to cool off on a hot day [source: American Academy of Dermatology].
Skin's complexion and texture can change over time, too. Probably the most dreaded sign of aging skin is the appearance of age spots, also called liver spots, which are flat areas of dark pigmentation that often appear on the face, chest, hands, arms and shoulders. In other words, those areas most exposed to the sun. They are caused by the production of excess melanin in the skin, a direct result of exposure to ultraviolet (UV) radiation [source: Mayo Clinic].
Another way in which skin changes as we age is in its ability to renew itself. Skin regenerates very fast in children, but the rate at which it renews gradually slows with age. Very old people's skin still regenerates, but it does so quite slowly. For this reason, older people experience a slower rate of healing when their skin is injured or infected. In fact, it may take an older adult's skin two to three times longer to heal than a younger adult's skin would [source: American Academy of Dermatology]. However, age isn't the only biological factor that determines one's risk of skin changes over time. Ethnicity may also play a role. For example, premature aging due to sun damage is less pronounced in people with darker skin [source: American Academy of Dermatology]. Also, there are a number of factors in the external environment that can cause premature aging -- keep reading to learn more.