The skin dehydration is manifested by a loss of splendor and well-being, with a more or less intense and persistent feeling of tightness: the skin is tight, especially after cleaning, and scales may also appear . It is an unusual and temporary state, which does not have to be associated with a “dry” type of skin peels. That is, a greasy skin can perfectly go through episodes of dehydration.
WHAT ARE THE CAUSES OF SKIN DEHYDRATION
- Water, like air, is an essential element for life. In adults, it accounts for around 65% of the total weight. Thus, a person of 70 kg is constituted of approximately 49 liters of water, of which 15% are concentrated in the skin.
- The role of water is fundamental. The water, a whole nursery where the other organs are supplied, allows the exchange with the outside: the water moves from the dermis to the surface, soaking the different layers to disperse. This water flow is called PIA (insensible water loss). The horny layer (upper layer of the epidermis), naturally protected by a hydrolipidic film on the surface, slows down the evaporation process. If this physiological barrier is altered, the PIE accelerates and the skin becomes dry. The water present in the dermis stops circulating to the epidermis , the hydrolipidic film no longer fulfills its function. Epidermis ), naturally protected by a hydro lipid film on the surface, slows down the evaporation process. If this physiological barrier is altered, the PIE accelerates and the skin becomes dry. Water present in dermis epidermis hydro lipid film
HOW DOES WATER REGULATION WORK ON THE SKIN?
The skin is very sensitive to any water deficit ; for this reason it is equipped with a hydroregulation mechanism.
70% of the skin is water. About 75% is found in the depth of the dermis dermis , where water plays an important role in the resistance of the skin. The hydration of the epidermis is the product of two elements: the static water, fixed and dynamic water circulating. Hydro regulation allows the balance between these two aqueous components, and is the only guarantee of the physical and functional integrity of the skin. In the hydro-regulation three main factors are involved: the NMF ( Natural Moisturizing Factors or natural factors of hydration), the lipids of the stratum cornea and a quaporins.epidermis lipids
Factors of hydro regulation, MFN (natural hydration factors)
NMFs are molecules that fix water in the stratum corneum ; they are called humectants. The most well-known MFN are urea and lactic acid. There are other substances, used in cosmetics, with the same properties, in particular glycerin and xylitol
THE BARRIER FUNCTION OF SKIN AND WATER
The stratum cornea is made up of cells that no longer have nuclei “cemented” by lipids , called intercorneocitic lipids . These lipids , in quantity and quality, are necessary for the integrity of the stratum cornea and, therefore, for its “barrier” function. When they are missing or deteriorate, the cohesion of the cells is no longer guaranteed. The result is an increase in the phenomenon of perspiration, also called insensible water loss (PIA, constant, light and natural evaporation of water present in the body).lipids lipids