Moisturizing the skin does not mean that we have to provide it with a lot of water. Intensive or frequent washing on the contrary, dries the skin. Then what should a moisturizing cosmetic do? How can a vegetable oil be moisturizing if it does not contain a single drop of water? A well-groomed skin has a hydrated appearance, so cosmetics called moisturizers are used - these obviously do not only moisturize but also help maintain the optimal level of hydration. Maintaining optimal skin hydration will be done with the help of ingredients that contribute to the proper functioning of skin cells, reduce environmental stress, strengthen the skin's own protective barrier.
The hydrolipid film - the stratum corneum contains elements that also prevent dehydration of the skin. When this protective barrier degrades, the skin dries, the skin structure is no longer intact, the reduction of the negative impact caused by free radicals does not work properly, the protection against contaminants does not work properly. The hydrolipid film acts as a lubricant, it is antimicrobial and provides the "acid coat" of the skin.
NMF compounds (Natural Moisturizing Factor). These compounds are hygroscopic, mainly amino acids, lactic acid, urea, sugars and mineral ions; they attract water from the atmosphere and combine it with the water from the cells, thus maintaining the hydration of the upper layer of the skin. NMF compounds are water soluble and will tend to be transported in water when the skin is washed, hence repeated or prolonged contact with water dries the skin.
Hydration of the deep layers of the skin is provided by glycosaminoglycans and proteoglycans from the dermis, especially hyaluronic acid. These are large polysaccharide-like molecules that have an increased ability to retain water. Glycosaminoglycans form an aqueous gel that ensures the volume of the skin and maintains its flexibility.