The skin serves as the body’s natural protective covering. It prevents germs and other potentially harmful agents from entering the body. The skin is also indicator of health problems.

Exposure to ultraviolet light, UVA or UVB, from sunlight accounts for 90% of the symptoms of premature skin aging. Most of the photoaging effects occur by age 20. The amount of damage to the skin caused by the sun is determined by the total lifetime amount of radiation exposure and the person's pigment protection. Wearing sunscreen every day is vitally important because it will repair current damage and prevent future damage.

Chronological Aging and Wrinkles
As a person ages the epidermal cells become thinner and less sticky. The thinner cells make the skin look noticeably thinner. The decreased stickiness of the cells decreases the effectiveness of the barrier function allowing moisture to be released instead of being kept in the skin. This causes dryness. The number of epidermal cells decreases by 10% per decade and they divide more slowly as we age making the skin less able to repair itself quickly.

The effects of aging on the dermal layer are significant. Not only does the dermal layer thin, but also less collagen is produced, and the elastin fibers that provide elasticity wear out. These changes in the scaffolding of the skin cause the skin to wrinkle and sag. Also, sebaceous glands get bigger but produce less sebum, and the number of sweat glands decreases. Both of these changes lead to skin dryness.

In the subcutaneous layer the fat cells get smaller with age. This leads to more noticeable wrinkles and sagging, as the fat cells cannot "fill in" the damage from the other layers.

Free Radicals and Wrinkles
Free radicals are unstable oxygen molecules that have only one electron instead of two. Because electrons are found in pairs the molecule must scavenge other molecules for another electron. When the second molecule looses its electron to the first molecule, it must then find another electron repeating the process. This process can damage cell function and alter genetic material. Free radical damage causes wrinkles by activating the metalloproteinases that break down collagen. There are several factors that start this cascading process including exposure to even small amounts of UV radiation in sunlight, smoking, and exposure to air pollution. For this reason, applying topical antioxidants on a daily basis is crucial.

The outside layer of skin that functions as a barrier to the external environment. The cells of the epidermis, keratinocytes, move from the bottom layer of the epidermis to the top layer building up a large amount of keratin and developing a tough outer shell. Once these cells reach the top layer, they flake off. If this process becomes abnormal the skin can look dull, leathery and show signs of wrinkles.


The second layer of skin is the dermis, which contains the structural elements of the skin, the connective tissue. There are various types of connective tissue with different functions. For example, collagen gives the skin its strength, proteins called glycosaminoglycans give the skin its hydration and elastin fibers give the skin its elasticity or spring.


The bottom layer of skin is the subcutaneous tissue, containing fat cells.