A Fresh Start: The Importance of Skin Exfoliation 

A Remarkable Process 

Your skin, that amazing organ that accounts for about fifteen percent of your total body weight, not only covers, supports, and protects all of your other organs, it also has the remarkable ability to continually repair and renew itself.  

Skin is chemically about 70% water, 25% protein, and 2% lipids, while the remaining 3% consists of trace minerals, nucleic acids, glycosoaminoglycans, proteoglycans and various other chemicals. 

Human skin is comprised of three layers, the epidermis, the dermis, and the subcutaneous, and varies in composition and thickness throughout the body.  The miracle of exfoliation and skin cell renewal takes place in the epidermis, the outer layer, which is approximately ½ to millimeter thick.

The cells of the uppermost layer of the epidermis �" the status corneum, or horny layer �" is a protective crust consisting of continually shedding dead cells (keratinocytes, the primary type of epidermis cells), hardened proteins (keratins, which protect against harmful substances), and lipids (fat-like compounds).  The average person sheds 2-3 billion skin cells daily, and the entire skin surface is renewed every three to five weeks. 

The middle layer of the epidermis contains vital living keratinocytes, or squamous cells, which do the main work of protecting the body. 

The inner layer of the epidermis, the basal layer, consists of basal cells which continually divide to form new keratinocytes.  As they are formed they move into the middle layer to perform their protective functions.  As they mature, keratinocytes lose water, flatten out and move upward, eventually reaching the status corneum where they are then shed, to be replaced by new cells moving upward from the middle layer. 

The rate at which natural exfoliation takes place depends on internal factors such as health, age, and the amount of moisture in the skin, as well as on external factors such as protective covering, temperature, and weather conditions.

The condition of your epidermis determines whether you have a fresh, glowing, youthful look or a rough, discolored, dull complexion.  The condition of your epidermis does not, however, determine whether you have creases or wrinkles.  Wrinkles are formed due to changes that occur in the inner layers of the skin, not in the epidermis.

The Effects of Aging 

As the body ages, or in the event of a debilitating illness, changes take place in the dermis and subcutaneous layers of the skin which effectively slow down the natural exfoliation process in the epidermis.  Dead cells pile up, leaving the surface scaly, discolored, and dull.

Exciting research is being carried out to more fully understand the human aging process and, of course, to determine what can be done to slow down that process. 

Without getting too technical, let’s consider one aspect of cell aging which has an impact specifically on skin.

Cellular Senescence  

In the early 1960s, scientist Leonard Hayflick observed that human fibroblasts in culture would divide about fifty times and then stop. Fibroblasts are connective tissue cells found in the dermis layer of the skin.  These cells synthesize collagen, elastin and other structural molecules, and their proper functioning is crucial to overall skin health.    

Hayflick observed that when fibroblasts approach fifty divisions they lose the ability to divide and begin to look and behave "old”.  Their metabolic activity decreases, they enlarge, and they accumulate lipofuscin, the pigment responsible for age spots. This state is called cellular senescence. 

It appears that in some tissues, such as the human skin, this so-called “Hayflick limit” may be an important part of the aging process.  While the number of divisions before a cell reaches its limit is not fixed, the accumulation of dysfunctional cells approaching the Hayflick limit appears to cause problems. Most cells, instead of dying, enlarge, lose their useful functions, slow down and interfere with newer cells. It was found that the skin of older people has about three times as much senescent fibroblasts as the skin of young people.

Slowing the Effects of Skin Aging 

It has been observed that various factors in the environment either speed up or slow down the cellular clock.  Increased free radical formation was shown to shorten the Hayflick limit, thus speeding up aging.  Some agents - antioxidants - were found to extend the limit in certain cell types. In one study, retinoic acid extended the Hayflick limit of fibroblasts in culture by almost 50 percent.

Improving your body’s environment, internally and externally, means minimizing exposure to factors that promote stress and unnecessary cell division, such as free radicals, inflammation, mutagens, some toxins and UV radiation.  Good nutrition, maintaining a normal body weight, and following a good exercise routine are all good ways to improve your body’s internal environment.  Avoiding overexposure to the sun and maintaining good skin hygiene are important ways to improve your body’s external environment. 

Non-surgical Skin Resurfacing

Another method of slowing the cellular clock is to artificially remove senescent cells from aging skin tissues without harming active, healthy cells; in effect, speeding up the natural process of exfoliation to the rate it once needed to maintain a fresh youthful surface.  Modern methods of removing dead and malfunctioning skin cells include chemical peeling, microdermabrasion, and intense pulsed light treatments. 

These are all essentially specialized techniques for destroying and removing old skin cells and triggering the body’s natural response to replace them with fresh new skin cells.  The cells may be removed by chemically burning off the top layers, mechanically sanding off the top layers, or burning targeted cells in specific layers using a light beam (either laser or non-laser) of a specific wavelength.

If your regular skin care regime includes a skin cleanser which contains a chemical exfoliating agent you are already in effect using a ‘light chemical peel’.  Dermologists and plastic surgeons use chemicals of varying strengths to remove skin cells in carefully monitored procedures followed by a controlled healing process. 

You may have also experimented with some of the over the counter masks and deep cleansers with varying results.  Formulas which contain some form of abrasive are in fact mechanically “sanding” off the dead skin cells from your epidermis. 

The use of nonablative laser and intense light treatments are only performed by dermatologists and plastic surgeons to treat specific problem areas of the skin.  These methods are based on selective photothermolysis whereby a targeted beam of light selectively heats up and damages a particular skin structure without affecting the surrounding tissue. This targeted ‘damage and heal’ treatment can be used to dissolve spider veins and age spots, reduce wrinkles, and tighten specific areas.

Your First Step

If you think you could benefit from an exfoliation procedure your first step should be to seek the professional advice of a board certified plastic surgeon or licensed dermatologist.  Skin renewal procedures can be absolutely safe and effective when performed by an experienced expert, but can go badly wrong when not administered correctly.  What may have worked for a friend or co-worker may not work for you. Suiting a procedure - or in many instances a combination of procedures - to your individual skin type and expectations is something that a physician can best determine.