Why is “skin barrier integrity” so important in Cosmetic Science?

Skin Barrier Integrity is an extremely important concept in skin care. It mainly refers to the stratum corneum (outermost layer of the epidermis) and describes the strength and resilience of the skin and how well it protects the internal tissues and organs from external aggressions. Desquamation (shedding) of skin barrier helps remove bacteria and other infectious agents that have adhered to the epithelial surfaces. The skin barrier is highly impermeable, a characteristic designed to prevent the loss of water out of the skin and to keep out damaging agents such as bacteria, viruses, chemicals, oxidants, pollutants, smoke particles, UV radiations, etc. It is the front shield of the innate immune system, acting as the first line of defense against invading microorganisms.

Keeping the skin barrier function in good condition fits entirely into the general definition of “cosmetic product”: “… any substance or mixture intended to be placed in contact with the external parts of the human body (epidermis, hair system, nails, lips and external genital organs) or with the teeth and the mucous membranes of the oral cavity with a view exclusively or mainly to cleaning them, perfuming them, changing their appearance, protecting them, keeping them in good condition or correcting body odours” (Regulation (EC) no 1223/2009 of 30 November 2009 on cosmetics products, art. 2).