Advice on how and why to do a correct facial skin exfoliation.

The visible surface of the skin is made up of "non-living" cells

It is made up of various overlapping layers of cells, physically and intimately joined to each other without any free space between them. One can imagine the arrangement of the epidermal cells as that of a brick wall.

The main function of the epidermis is protective.

At the same time, the fabric must be elastic and allow for movement, with a certain ability to expand and contract in the event of changes in body weight.

To fulfill these tasks, the skin surface is not inert and immutable but, on the contrary, in continuous renewal, the surface cells detach themselves thousands at a time, following a process of constant exfoliation throughout the year called skin turnover, absolutely imperceptible in conditions physiological.

Why is the skin surface constantly renewed, but the skin does not thin?

The surface cells are completely replaced approximately once a month.

The overall epidermis does not reduce in thickness because the cells that detach are replaced by others, newly formed in the innermost area adjacent to the dermis, called the "basal layer"

The epidermal cells of the basal layer are alive and reproduce; from a mother cell, two exactly identical daughter cells arise.

Subsequently, one of the two remains identical to the mother cell, with the possibility of giving rise to new cells: the other, however, begins to produce a substance called "keratin" in large quantities.

Keratin is the most important protein of the epidermis and skin appendages such as hair, hair and nails. It is very resistant, thanks to its fibrous nature and insoluble in water.

In physiological conditions, skin turnover corresponds approximately to a period of one month, so at the end of a calendar year we can hypothesize that we have "lost" approximately 2 kg of skin cells.

At a certain point the amount of keratin inside the cell is so high that it causes its death, one can say through a sort of "suffocation". The cell loses its nucleus and at the end of the maturation process it reaches the surface of the epidermis with a very particular physical structure: it is similar to a thinned scale, extremely resistant and waterproof thanks to the keratin of which it is mostly made.

In pathological situations, such as in the case of psoriasis, the turnover is reduced enormously, even reaching a week. This means that the epidermal cells do not have the necessary time to "mature" regularly. It is likely that they reach the surface still alive and not sufficiently rich in keratin. In this way the main defensive and protective characteristic of the skin is missing, consequently the skin is weaker.

It is no coincidence that psoriasis is a disease of psychosomatic origin which explains the strong connection between the central nervous system and the epidermis; Furthermore, the patient feels psychologically more fragile and has fewer defenses against the outside world.

How the epidermis changes with aging

The main changes in the epidermis over the years can be summarized as follows.

› Cell turnover slows down, particularly from 40-45 years of age onwards. As a result, the skin surface no longer renews itself regularly once a month, the corneocytes detach more slowly and, thus, remain "attached" to the skin for a longer time. This leads to a sort of "concrete effect", in the sense that the aged horny cells give the complexion a dull appearance, with a grayish tone just like... concrete!

  • The epidermis reduces in thickness and, especially after menopause, becomes less elastic and toned.
  • The hydrolipidic film changes both in composition and quantity and tends to decrease over time, so the skin dehydrates more quickly and is also more exposed to the external environment.
  • Pigmentation frequently becomes uneven. Already around the age of 30, hyperpigmented areas may appear compared to lighter ones. The phenomenon worsens following prolonged exposure to sun rays over the years without adequate protection, especially if sunburn occurred in youth.


We have seen how slowed physiological epidermal renewal is one of the effects of aging. The result of the increased permanence of cells on the skin surface leads to greater opacity, with a reduction in elasticity and overall hydration of the skin.

Promoting epidermal turnover does not only mean promoting the exfoliation of dead cells that tend to "cement", but also stimulating the basal layer for the formation of new cells. The result is visible: the skin surface that renews itself regains brightness and improves softness and the complexion.

What are the cosmetic techniques that promote epidermal turnover?

They can essentially be traced back to two types: chemical and mechanical.

  • The former are based on the use of chemically active substances such as alpha-hydroxy acids, in concentrations higher than 18% and with a pH lower than 3, beta-hydroxy acids (for example, salicylic acid), or derivatives of retinoic acid.
  • The mechanical exfoliation system involves the use of very fine powders obtained from aluminum salts, or from the final product of the processing of precious stones, such as diamond or mother-of-pearl, which cause a microdermabrasion on the surface of the epidermis.

What is the difference between exfoliation and peeling?

Exfoliation means a delicate process of removing superficial horny cells that are already in the process of detachment. It is a cosmetic treatment without side effects, which can also be carried out at home. For this reason we have created two types of mechanical exfoliants GOMMAGE OH MERVEILLE almonds and bamboo and GOMMAGE SB PROBIOTICS with micronized apricot kernel.

Peeling, on the other hand, involves the elimination of several layers of skin cells and, if on the one hand it is particularly effective, on the other it is aggressive and dangerous due to potentially irreversible side effects. It should only be performed under medical supervision by a dermatologist.

Chemical peeling involves the application of glycolic, salicylic or trichloroacetic acid at a very high concentration and with a minimum pH, for a duration of a few seconds.

At what age are cosmetics that promote epidermal turnover recommended?

It depends above all on the type of skin, rather than on age.

As anti-aging, cosmetics that act on skin turnover are recommended from the age of 35, with periodic use, depending on the type of skin, from 1-2 times a week to 1-2 times a month.

Normal-combination skin has a greater need, compared to dry skin, to promote skin exfoliation, to reduce sebum on the surface and reduce the formation of comedones which can lead to the formation of pimples.

If the skin is dry, each treatment with AHA should be tested on small areas first, because it must not cause redness which can sensitize the skin. For dry skin, a very delicate exfoliation is recommended, with glycolic acid in a concentration of no more than 8% and with a pH of no less than 4, or a treatment with very fine powders.

NB Retinoic acid is a molecule for medical-pharmacological use only.

The dermatological actions of retinoic acid concern:

  • increased superficial skin flaking;
  • the thinning of the stratum corneum;
  • promoting the formation of new keratinocytes;
  • a positive effect on fibroblasts.

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