• Lourdes Varadé, chemical engineer

    To exfoliate or not to exfoliate?

    17 Jun

    Since ancient times it seems to have been accepted that a healthy, flawless skin, free of dead cells, needs regular exfoliation. This body care ritual can be performed using products containing abrasive particles, layers of gomage which are then peeled off or creams with specific ingredients. Peeling, dermabrasion, scrubbing ... is exfoliation a necessity or an aberration?


    The outside layer of the skin is the epidermis, whose cells originate in the basal layer (which separates the epidermis from the dermis). These cells gradually migrate to the surface and then die. Healthy skin is renewed every 30 days. Aged skin has a longer renewal cycle.

    Keratinocytes, the most abundant cells in the epidermis, have a protective function. Dead keratinocytes accumulate in layers, fixed by a form of intercellular cement composed of lipids (fats). That way they do not shed more than is normal.

    How do we know that a keratinocyte is dead? Because its cell lacks a nucleus. How does an exfoliant know that a keratinocyte is dead? It doesn't know. Therefore, in exfoliating and scraping our skin, we not only remove dead cells, but also living cells and all types of microstructures present in our skin. Conclusion as to what we do when we exfoliate? We indiscriminately remove cells, microbiota and flora and other elements that ensure the health of our skin.


    Exfoliation in history

    Cosmetics are a sign of civilization. The ancient Egyptians used exfoliants, mentioned in the Ebers Papyrus: "Another [remedy] to make the surface of the flesh perfect: one part of powdered alabaster, one part of natron, one part of sea salt and one part of honey. Mix and rub on the skin.” (Ebers, 714)

    Cleopatra’s baths in donkey’s milk were famous. The truth is that the milk was sour, as fermented milk produces lactic acid. Lactic acid is an alpha hydroxy acid (AHA) which is today used in cosmetics.

    A predecessor of gomage was also used in Egypt. It was a viscous liquid consisting of a plant-based thickener dissolved in honey and vegetable oil, which was then applied to a recently washed face (Ebers, 719). Another variant was made with incense, moringa oil, wax and green cypress shoots (Ebers, 716).

    The Greeks set the aesthetic standards for our civilization, even though they did not know soap. They smeared themselves with oil and a layer of sand and then rubbed down the body before bathing. Was not that exfoliation?


    Mechanical exfoliation

    This is exfoliation proper, also called scrubbing. It is done with cosmetics containing abrasive particles or with horsehair gloves, brushes, sponges or other objects that make friction with the skin.

    The cosmetics may contain particles of polyethylene, pumice stone or of pips or peel from crushed fruit, for example, apricot or peach stones, strawberry seeds, almond or walnut shells and even crushed legumes – hence the ads for scrubs using apricots, almonds or azuki beans. Adding the exotic touch, they sometimes include Dead Sea salt, Himalayan salt, sugar cane, etc.


    Chemical exfoliation

    This kind of exfolitaion, called peeling, uses cosmetics whose formulation includes urea or the AHAs (alpha hydroxy acids) as active ingredients.

    Urea-based creams facilitate moisturizing of the epidermis and encourage desquamation by dissolving the intracellular cement between dead cells. They are used in concentrations between 2% and 10%.

    The AHAs, which were first used in cream formulations in the 1990s, help, like urea, with the sloughing process by removing the intracellular cement. At concentrations of 10% to 12% they act as exfoliants. Examples of AHAs include glycolic acid (from sugar cane or the famous snail slime), lactic acid (which Cleopatra was doing was a chemical peel), malic acid (from apples), citric acid and tartaric acid.



    Gomage involves spreading a sticky substance on the skin, usually on the face, waiting for it to dry and then peeling it off like a layer of skin. Another way to remove the mask is by rubbing the skin, resulting in what are called “mobile filaments” in cosmetics.



    If the skin renews its cells every month, does it make any sense to “sand” it once or twice a week, without giving it the chance to regenerate itself? The risks are:

    - Removing the protective horny layer makes the skin more vulnerable to sunlight.

    - Removing the hydrolipid film makes the skin more sensitive to certain agents and could lead it to develop a lifelong intolerance to a cosmetic.

    - Changing the flora reduces the skin’s protective barrier against microorganisms.


    Scrubs or peels?

    Scrubs have more disadvantages than advantages. The skin is not given a chance to regenerate. Today, with the life we lead and assuming that hygiene is daily, it is not necessary to exfoliate layers of skin to remove dirt.

    After a scrub the sensory effect of a smoother skin is immediately evident. What we think is great sensorially, however, was an assault on our skin. It was probably not necessary, but in the cosmetics sector as elsewhere, commercial success lies in getting yet another product on our shelves. It all depends on how critical and demanding we are as consumers.

    To genuinely work with the cell renewal process, the best thing we can do is to do chemical peels on an ongoing basis, for example, by daily using a gentle cream that contains urea or AHA. These creams are humectants that help slough off dead cells. Of course, the effect is not immediate. From a sensory standpoint, we will not suddenly feel that our skin is soft. However, ongoing use of this kind of cream will ensure that the skin looks beautiful and healthy.



    Dermatologic Therapy