The cell renewal factor (CRF) is a natural process that slows down with age. Babies renew their cells every 14 days, teenagers every 21 to 28 days, middle-age adults every 28-42 days and it takes 42-48 days to renew cells by age 50 or older. Many things influence our CRF like the environment, lifestyles, medical history, genetics and hygiene. The corneum layer of the epidermis consists of 15 to 20 layers. Excess dead skin cells accumulated on its surface. Exfoliation is defined as “peeling or sloughing of the horny outer layer of the skin, or corneum.”
Any ingredient that is used in this process is an exfoliant. Exfoliation is also called superficial peeling, keratolysis and desquamation. The surplus accumulation of skin cells, hyperkeratosis, is especially common in oily skin. Excess sebum clogs pores and causes dead skin cell build-up, which makes regular exfoliation essential for oily skin.
It is important to note that the esthetician works only on the superficial epidermis, leaving deeper exfoliation to physicians, who work in the live layers below the epidermis. Alpha hydroxyl acids (AHAs) started being used to exfoliate the superficial layers of the skin in the 1980s. AHAs derived from fruit became popular in the 1990s, and today, the advancement of exfoliation grows with innovations such as microdermabrasion.
There are two types of exfoliation: mechanical and chemical. Mechanical involves physically sloughing dead skin cells from the surface of the skin by the means of microdermabrasion, brush machines, or granular scrubs made with natural or synthetic materials. Chemical exfoliation involves chemical agents that dissolve the intercellular glue that binds dead skin cells together. Examples include enzymes, AHAs, trichloroacetic acid (TCA), glycolic & lactic acid and beta hydroxyl acids (BHAs) such as salicylic acid.
Benefits of exfoliation are many: stimulated blood flow, accelerated cell turnover rate, eased extractions, increased moisture retention for the skin, increased product penetration, and the skin is left smoother and with a more even tone. There are contraindications one should be aware of.