How Do Moisturizers Work?
July 8, 2011
The term moisturizer is often misconstrued by consumers as a product that increases the moisture content in the skin. Although a critical component of most skin care regimens, the moisture content of your skin is not directly increased with the application of moisturizers.
Acting to restore the wear surface by providing a protective film and covering tiny cracks restores the barrier function of the epidermis, which ultimately increases the water content retained in your skin. (http://www.medscape.com)
The mechanism of an effective moisturizer slows the evaporation of your skin’s moisture, which maintains hydration. Dry and aging skin appears and feels much softer with regular application of moisturizers.
STRUCTURE OF THE EPIDERMIS
The upper layer, or epidermis, of the skin is divided into 4 layers (top to bottom):
- Stratum Corneum
- Stratum Granulosum
- Stratum Spinosum
- Stratum Basale
Most cosmetic moisturizers contain 1 or more of 3 ingredient types:
- Humectants — including ingredients; glycerin, urea, and pyrrolidone carboxylic acid (PCA), attract water to the epidermis from the dermis. These ingredients also help maintain that moisture in the stratum corneum. Since humectants tend to have a tacky feel, their use is limited to reduce this negative effect.
- Occlusive Agents — minimize water loss from the epidermis by acting as a physical barrier. Occlusive ingredients include: petrolatum, waxes, oils and silicones. Since the fell of these agents tends to be quite heavy, they are usually combined with emollients to make the product lighter.
- Emollients — grouped according to ‘spreadability’ on your skin, smooth flakes and provide some occlusive action. Different type emollients are often mixed together to achieve the perfect feel on your skin.
- Jane Iredale