Cell turnover is the process by which the skin makes new skin cells. These cells, which live about two to three weeks, travel from the lowest layer of the epidermis to the top layer and then shed off. This process is what keeps dead cells from building up on the skin's surface. Unfortunately, skin cell turnover slows with age, so exfoliation is useful, but daily exfoliation is excessive.

According to Milady Standard Esthetics: Fundamentals, a baby's average rate of cell turnover is 14 days, while a teenager's average cell turnover rate is 21 to 28 days. A middle-aged person has an average rate of 28 to 42 days and those 50 and older shed cells every 42 to 84 days.

How Over-Exfoliation Affects Skin Conditions
Clients are sometimes surprised that they still have acne when they exfoliate daily; they do not realize that the skin is compensating for the loss of oils and is overproducing sebum. Clients with oily skin should be exfoliating two to three times a week.

Clients with dry, sensitive, and thin skin will benefit greatly if they limit their exfoliation to one to two times per week as the oils on the skin keep it moist and supple. Over-exfoliating will dry out their complexion and make wrinkles more prominent. Furthermore, they may experience couperose, exacerbated rosacea, and increased sun sensitivity.

Clients with conditions such as acne or cystic acne, couperose, rosacea, or hypopigmentation should avoid peels and over-exfoliation. Elderly clients, tan or sunburned clients, and types V and VI on the Fitzpatrick scale should also avoid peels and over-exfoliation.

Physical and Chemical Exfoliation
There are two types of exfoliants on the market: physical and chemical. Everything that is used to mechanically slough off dead skin is referred to as physical exfoliation, which includes scrubs, microdermabrasion, and rotating sonic brushes. This method is a very easy way to refresh the skin and it often appeals to both men and women.

Chemical exfoliation includes acids, peels, and enzymes. Enzymes are a wonderful way to safely exfoliate the skin without breaking capillaries and causing irritation. Enzymatic exfoliation is a beneficial, natural way to clean out the pores, remove excess oils, and slough off dry and dead skin for a healthy cell turnover. Fruit enzymes, such as bromelain from pineapple and papain from papaya, eat away at excess oils and dry skin to expose a refreshed, clear complexion. Enzyme masks are generally more gentle and safe than acids and do not thin the skin like Retin-A. Using an enzyme mask two or three times a week is sufficient; steaming masks helps to further pull out impurities.