The skin contains between 60% to 80% water depending on age, the majority of which is located in the dermis: the proteoglycans that make up the dermis bind significant quantities of water molecules. The stratum corneum, the most superficial layer of the skin, contains 13% to 15% water. The skin is said to be dehydrated when this percentage falls below 10%. The stratum corneum becomes rough, brittle, and loses its integrity.
Dehydrated skin is due to a failure in the hydrolipidic barrier which is no longer able to retain water. Skin dehydration is often linked to environmental factors (cold, wind, pollution, sun, etc...), stress, fatigue, lifestyle (smoking, insufficient hydration, alcohol consumption, use of overly harsh/stripping cosmetic products) and the intake of certain medicinal treatments (anti-cholesterol, anti-acne, etc...).
All skin types require hydration. However, it is even more urgent to act on dehydrated skin. Papyrus native cells limit insensible water loss (IWL), that is, the natural evaporation of water through the skin. On the other hand, they promote the creation of lipids (free fatty acids, cholesterol, ceramides, etc...) which are found in the horny layer of the epidermis, the very ones that help maintain cohesion between the corneocytes, the cells of the horny layer that act as a skin barrier. Thanks to this improved hydrolipidic balance, the epidermis limits its dryness and ensures better protection against external aggressions.