Anyone can be affected by dry skin at one time or another. Some people have dry skin due to their genetic makeup, others can suffer from it at times in their life due to external factors. To take care of dry skin, it is important to know its characteristics and identify the active ingredients it needs to stay beautiful.

The skin is the most extensive organ in the human body since it represents 16% of its total weight. It plays several important roles in the body: the skin protects us against external aggressions (shocks, pollution …), helps the body to regulate its temperature, participates in the production of vitamin D and hormones and defends us against them. infections through its own immune system (led by keratinocytes). Our skin is organized in several layers.

The skin is a complex organ that is organized into several layers that overlap:

• The epidermis: it’s about the surface layer of the skin composed of three types of cells: keratinocytes (a mixture of keratin and lipids), melanocytes (cells that pigment the skin) and langherans cells (the skin’s immune system). The epidermis plays a protective role because it is semi-permeable. 
• The dermis, the middle layer : It is located under the epidermis and supports it. It is divided into two layers, the papillary dermis and the reticular dermis rich in nerve endings and elastic fibers. These two layers contain fibroblasts (which produce collagen) and immune cells (histiocytes and mast cells). 
• L’hypoderme, the deep layer of the skin : laced under the dermis, the hypodermis is adipose tissue, that is to say composed of fat. Nerves and blood vessels pass through the hypodermis to the dermis. The hypodermis is a fat storage place, it protects the bones by acting as a shock absorber, it keeps heat and shapes the silhouette.

These different layers contain 70% water, 27,5% protein, 2% fat and 0,5% mineral salts and trace elements.

Dry skin is a kind of skin, like oily or combination skin. It is characterized by tightness, tingling and visible skin symptoms such as roughness, peeling and a dull complexion. People with dry skin may also have more pronounced skin aging than the others (deep wrinkles). The main cause of dry skin is the lack of lipids: the sebaceous glands fail to produce enough sebum to form a protective film on the skin. The tightness and tingling of the skin also occurs when the skin is dehydrated, this is called punctual dryness of the skin. In question, external aggressions such as cold, dry wind, pollution, the sun, but also the lack of internal and external hydration. Age is also a risk factor for dryness because over time the skin’s metabolism slows down.

Dry skin therefore needs to be nourished and hydrated in depth. The hydration of the skin begins with a good supply of water. That is why it is recommended to drink 1,5 to 2 liters of water per day. In addition, people with dry skin must apply daily care products rich in water-derived agents, natural moisturizing factors (also called Natural Moisturizing Factors or NMF) and lipids to nourish it deeply. 

A star molecule in skin care for several years, urea is one of the Natural Moisturizing Factors, so-called “hygroscopic” agents. NMFs are naturally present inside corneocytes (cells in the epidermis) and have the role of attracting and retaining water. In addition to urea, there are lactic acid, amino acids, carbohydrates and mineral ions (chloride, sodium and potassium) among the NMFs. 

Urea in the body comes from the breakdown of proteins by the body. This molecule is made by the liver and eliminated in the urine. Urea found in moisturizing skin care is now synthesized in the laboratory from ammonia and carbon dioxide. Well tolerated by all skin types, urea is renowned for its keratolytic (it gently exfoliates the skin), antibacterial and moisturizing (it absorbs and retains water) action. By binding to water molecules, urea retains them in the surface layers of the epidermis. This molecule is therefore particularly suitable for skin with calluses, acne-prone skin, sensitive skin and dry skin.