Читать книгу The Complete Make-Up and Beauty Book - Leigh Toselli - Страница 19

With the beauty focus now falling on added extras – antioxidants, fruit acids and sun protection – there’s a tendency to forget that water is the basic common denominator, making up around 60 per cent of a typical skin-care product.

How do you know when a skin is thirsty? Dryness and tightness are the most obvious signs, but these are common to both dry and dehydrated skins – essentially two different conditions. Dehydrated skin may be naturally dry, normal or oily, but happens to be temporarily lacking in water. A good way to test for dehydration is to stand close to a mirror and move the skin of the cheek gently upward with the index finger. A dehydrated skin will fold into a tightly packed range of lines or ripples.

Taking in enough water, both externally and internally, is therefore crucial to preventing dehydration. When we become severely dehydrated, the skin’s lower layer, which is 80 per cent water, ‘donates’ water to the rest of the body. Without water in the upper layer, enzyme activity slows down, skin becomes thinner, water evaporation accelerates and external aggressors penetrate easily.

If skin is not treated immediately, the skin deteriorates quickly, becoming fragile and irritated. The only way to break the cycle is to provide the skin with intensive, long-lasting hydration and to stimulate enzyme activity with an effective moisturizer.

A product’s moisturizing abilities are also determined by the humectants it contains. These work by either drawing water up from the depths of the dermis or attracting it from the surrounding atmosphere. Look for hyaluronic acid, sodium PCA, propylene, butylene glycol or marine extracts.