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The Science of Aging Skin
By: Lydia Sarfati
Posted: June 1, 2009, from the June 2009 issue of Skin Inc. magazine.
From the moment a person is born, aging begins. Although you are powerless to the natural process of aging, what is done each day will affect the skin later. The rate at which the skin bears the signs of aging is dependent not only upon chronology and genetics, but also on the environment, a very large factor working against the skin that many tend to overlook during their youth.
As a person ages naturally, several changes take place gradually in the skin. The stratum corneum is the outermost layer of the epidermis, composed of flat, platelike envelopes filled with keratin, a protein that prevents water evaporation. Plump cells are continuously traveling from the lower layers of the epidermis to the upper layers. When they reach the surface, they will have become flat and scaly, at which point they are sloughed off in a process called desquamation. As aging occurs, desquamation changes, resulting in a thicker layer of dead skin cells making the surface uneven and sometimes dull. Production of keratin also slows, which, in turn, means drier skin. The epidermis as a whole will also become thinner and more transparent.
Hormonal changes, mainly due to menopause, cause a reduction in sebum production. Sebum is an oily, lipid-rich film that covers the skin’s surface, providing natural lubrication. Mixed with perspiration, the skin’s surface becomes slightly acidic, keeping some bacteria and fungi from entering and helping to retain water in the tissue by slow evaporation from the surface. Slower production of sebum will again result in dehydrated skin.
Elastic properties and skin’s firmness change during the aging process as enzymes break down the elastin and collagen proteins. Elastin provides resiliency to the skin; its natural ability to snap back. Collagen provides strength to the skin structure. The degradation of these proteins will ultimately lead to wrinkles as dehydrated skin loosens.
Most people are born with beautiful skin; however, the lifestyles they lead will have an impact on how they age. Extrinsic factors, such as sun exposure, will expedite the signs of aging on the skin.