HomeThe science of cosmeticsUnderstanding our skin

What makes our skin the way it is?

Everyday we wash, buff and apply creams to our skin, but how much do we really know about the complex structure covering our bodies?

In simple terms, our skin is made up of three distinct layers: the top or outer layer called the epidermis; the second layer called the dermis, which contains blood vessels, nerve endings, hair roots and sweat glands; and finally the subcutaneous fat layer containing larger blood vessels and nerves.

We all appreciate that when our skin is dry it often feels rough and flaky. It's the top layer of the epidermis - the stratum corneum - that plays a key role in helping contain moisture within the skin. Normally up to 15% of the stratum corneum consists of water. When the moisture content of the stratum corneum falls below 10% the skin appears dry and flaky; further drying can lead to reduced flexibility and cracking.


The spaces between the cells in the epidermis are packed with fats, or lipids, and other components. A mixture of amino acids and salts, which are water soluble and present within the cells and help the cells hold in their moisture, is known as the "natural moisturising factor". This is important as it helps the stratum corneum regulate natural water loss by preventing water evaporating from deeper layers of the skin.

The mixture of amino acids and salts are easily washed out (being water soluble), which reduces the ability of the cells at the surface to hold on to their moisture. Sometimes when we use strong soaps or detergents, or are exposed to solvents, these valuable components are washed out and the skin loses some of its ability to keep water, it then becomes dry and will start to crack.

Skin cells are constantly being renewed and the dead cells shed. The epidermis contains natural enzymes that are important for getting rid of old skin cells. These enzymes need moisture to work properly.

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