Live Beautifully, Age Gracefully.

Decoding Skin Surface Renewal


By: Paolo Giacomoni, PhD. Posted: 11/12/2015

Skin is the largest organ of the human body. In adults, its surface ranges between 9 and 18 square feet with a weight of about 2.2 to 4.4 lbs.

Skin is composed of “compartments”:
The epidermis is the interface between the body and the outer world, and it contains part of the skin’s immune system, its tactile functions and the pigmentary units.

  • The hypodermis, which covers fat tissue
  • The dermis, made of elastic fibers and water-binding macromolecules forming the ground substance, and containing blood vessels, sweat glands and sebaceous glands
  • The epidermis, which covers the dermis

The top of the epidermis consists of several layers of corneocytes. These are improperly believed to be dead cells. They constitute the stratum corneum (Latin for horny layer), which contains a wealth of enzymes whose presence is essential to its proper function. Beneath the stratum corneum there is the so-called living epidermis.

The epidermis undergoes a daily, permanent renewal process. Every keratinocyte in the basal, or bottom, layer gives “birth” to a daughter cell and pushes up the cells to the suprabasal layers. And the corneocytes in the outermost sheet of the stratum corneum shed off from the epidermis.

This shedding-off process is called exfoliation, and it’s governed by the stratum corneum. Because exfoliation occurs disorderly, however, the surface of the epidermis is left in a wholly unpolished state. This affects the luminosity of skin in the same way that dust makes a mahogany table appear dull. It also enhances the visibility of surface imperfections, such as lines and fine wrinkles.

The best way to improve the youthful aspect of one’s skin is to polish the epidermis, thus removing the outer corneocytes.

A dermatologist can provoke a peeling with facial chemical peels containing phenol, tri-chloro-acetic or glycolic acid. One can also apply skin care products containing diluted alpha-hydroxy acids or salicylic acid. These acids, though, cannot be used in the delicate contour of the eye—where their action would be most desirable—because they might be irritants.

Perhaps the safest and most effective way to achieve smooth, polished skin is to act in tandem with the renewal of the epidermis. One should use scientifically proven botanicals, such as chestnut extract, that activate the natural exfoliation process in the stratum corneum. The use of such botanicals is not limited by skin type, though this is most appropriate for sensitive skin. Quite beneficially, these extracts can also be applied to the skin around the eyes.