Water is essential for the proper functioning and renewal of epidermal cells. The superficial cells of the stratum corneum are responsible for the skin's appearance and texture. When skin is dehydrated, its quality is altered. It typically becomes rough, dull and lacks suppleness. Under these conditions, dehydrated skin is more susceptible to the passage of potentially toxic or allergenic substances. It therefore becomes more sensitive and reactive. All skin types can be dehydrated, even oily skin.
For skin to be properly hydrated and therefore "comfortable", it needs 13% water in the superficial layers of the epidermis. This level of comfort is best achieved if the skin is properly hydrated from within, and if the intercellular cement is of good quality. So, long live vegetable oils!
Causes of skin dehydration
The environment: heat, dry air and wind aggravate water loss due to evaporation. Conversely, a humid environment reduces water loss.
Unsuitable skin care: the use of cleansers containing harsh chemical soaps that are not offset by a high-quality natural cream. Frequent cleansing and exfoliation alter the hydrolipidic film.
Aging: the main factor aggravating cutaneous dehydration is the reduction in sebum production with age, and also during menopause.
An unbalanced diet: lack of oils rich in fatty acids.
The natural regulation of skin hydration
Water is constantly supplied to the skin by blood circulation in the dermis, then by diffusion to the epidermis, hence the importance of drinking enough water every day. Also, the skin is unable to draw water from the outside. At the same time, it continually loses water through perspiration and evaporation. Hydration of the epidermis therefore depends on the balance between water loss and supply. The lipid cement, the cell membrane and the hydrolipidic film slow down water evaporation, and this is what we call the « cutaneous barrier ».
Replacement elements
As the skin is almost impermeable to external water, only a small quantity can penetrate between the dead cells in the desquamation phase.
In cosmetics, moisturizing products work by reproducing the skin's natural functions. They reduce water loss by counteracting evaporation through film-forming, emollient and humectant agents which, like tiny sponges, retain and draw water from the dermis into the cells. Humectants have a deeper action. Emollient agents smooth, soften and protect the skin's surface by filling the micro-cracks that form between the cells of the superficial layers of the epidermis.
Natural moisturizing ingredients
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Film-forming ingredients slow the evaporation of water.
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Natural waxes, large-molecule hyaluronic acid, plant collagen, aloe vera gel, lanolin, etc.
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Emollients smooth, protect and fill micro-cracks.
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Vegetable oils and butters, ceramides, fatty alcohols, fatty acids.
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Humectants act deep down to bind hygroscopic water.
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Proteins, amino acids, MNF, glycerin, lactic acid, AHA, urea, honey, yogurt, aloe vera, algae, ultra-small-molecule hyaluronic acid.
Every day
Skin hydration is closely linked to the hydration of the body itself. With this in mind, we recommend drinking 1.5-2 liters of water a day. Dry, dehydrated skin can also be the result of a dietary imbalance. Try to consume raw, organic, first cold-pressed oils rich in unsaturated fats.
Gentle exfoliation once a week helps to maintain skin quality by stimulating cutaneous renewal, allowing products to penetrate better.
The difference between dry and dehydrated skin?
Moisturization is a key factor, and even the focus of consumer expectations and cosmetics industry innovations. And that's easy to understand when you consider that dehydration is the number one skin problem experienced by women.
Dry skin is rarer than dehydrated skin!
Did you know that oily skin can sometimes suffer from dehydration? In fact, skin hydration levels depend on the quality of intercellular cement and the amount of water contained in skin cells. Epidermal cement is made up of essential fatty acids that may be lacking in the diet. These lipids can lose their watertightness in periods of cold, wind or various climatic aggressions.
How to tell the difference between dry and dehydrated skin...
Dry skin?
Dry skin suffers from a lack of oil, i.e. fatty acids, at all levels of the epidermis: not enough ceramides, essential fatty acids and complex lipids in the intercellular cement, the result? Chronic, excessive water loss. What's more, true dry skin can't fulfill its barrier role because its hydrolipidic film is of poor quality. For genetic reasons, sebum production is too low. As a result, the skin peels and becomes irritated more easily. Dry skin can be recognized by its rough, cracked appearance.
Dehydrated skin?
Dehydrated skin is not, strictly speaking, a skin type in itself. All skin types can experience dehydration at one time or another. The lack of water originates in the dermis and the irrigation of its cells. The skin is poorly « nourished » and « irrigated ».
The causes? Food and drink: a lack of water, water-soluble vitamins and oxygen.
On the other hand, the symptoms of dehydrated skin are quite similar to those of dry skin... Tightness and discomfort throughout the day, desquamation (often localized on the wings of the nose or eyebrows) and a dull complexion.
2019 is distinguished by new ingredients (new plant extracts, the presence of probiotics...), and concepts that are being confirmed, such as neuro-cosmetics and anti-pollution. As for hyaluronic acid, it is omnipresent. Whatever the case, and whatever the added value put forward, hydration remains the skin's most eternal need...
ref: Oleassence, cosmetics observatory