Page 237 - Cosmetology

myristic acid. Detergent cleansing agent that also creates foam and can be drying. See surfactant.

myristyl myristate. Used in cosmetics as a thickening agent and emollient.

myrrh. Fragrant gum resin that can be a skin irritant. There is little research showing it to have any benefit
for skin, though there is a small amount of research showing it may have antifungal and antibacterial
properties.

myrtle extract. Contains volatile oil and tannins. It can have fungicidal, disinfectant, and antibacterial
properties. It contains 1,8-cineole, a constituent responsible for toxicity. It is recommended that this not
come in contact with skin.
Myrtus communis extract. See myrtle extract (above).

Mytilus edulis byssus extract. Extract of the blue mussel. There is no research showing it to have benefit
for skin.
N

N6-furfuryladenine. Technical name for kinetin. See kinetin.

N-acetyl-L tyrosine. See tyrosine.

NaPCA. See natural moisturizing factors and sodium PCA.

Narcissus poeticus wax. Fragrant flower extract that can cause irritation and dermatitis.

Nardost achys jatamaus. See spikenard.

Nasturtium officinale extract. See watercress extract.

natto gum. Fermentation product of soy protein. It may be a potent antioxidant.

natural ingredients. The FDA has tried to establish official definitions and guidelines for the use of certain
terms such as "natural" and "hypoallergenic," but its regulations were overturned in court. That means that
cosmetics companies can use these terms on ingredient labels to mean anything they want, with the result
that it almost always means nothing at all. The term "all-natural" has considerable market value in promoting
cosmetic products to consumers, but a close look at an ingredient label reveals that the plant extracts make
up only a small percentage of the product. Plus, when a plant is added to a cosmetic, preserved, and
stabilized with other ingredients, it loses its natural qualities.

natural moisturizing factors. One of the primary elements in keeping skin healthy is making sure the
structure of the epidermis (outer layer of skin) is intact. That structure is defined and created by skin cells
that are held together by the intercellular matrix. The intercellular matrix is the "glue" or “mortar” between
skin cells that keep them together. It helps prevent individual skin cells from losing water and creates the
smooth, non-flaky appearance of healthy, intact skin. The components that do this are often called natural
moisturizing factors (NMFs) or ingredients that mimic the structure and function of healthy skin. While the oil
and fat components of skin prevent evaporation and provide lubrication to the surface of skin, it is actually
the intercellular matrix along with the skin's lipid content that gives skin a good deal of its surface texture and
feel.

The intercellular matrix is the skin’s first line of defense against water loss. When the lipid and NMF content
of skin is reduced, we experience surface roughness, flaking, fine lines, and a tight, uncomfortable feeling.
The longer the skin’s surface layer (stratum corneum) is impaired, the less effective the skin’s intercellular
matrix becomes. Moreover, the skin's healing process is impaired. NMFs make up an expansive group of
ingredients that include amino acids, ceramides, hyaluronic acid, cholesterol, fatty acids, triglycerides,
phospholipids, glycosphingolipids, urea, linoleic acid, glycosaminoglycans, glycerin, mucopolysaccharide,
and sodium PCA (pyrrolidone carboxylic acid). Ingredients that mimic the lipid content of skin are apricot oil,
canola oil, coconut oil, corn oil, jojoba oil, jojoba wax, lanolin, lecithin, olive oil, safflower oil, sesame oil,
shea butter, soybean oil, squalane, and sweet almond oil, which can all be extremely helpful for making dry
skin look and feel better.

All of the skin's supporting NMFs and lipids are present in the intercellular structure of the epidermis, both
between skin cells and in the lipid content on the surface of skin. When any of these ingredients are used in
skin-care products, they appear to help stabilize and maintain this complex intercellular-skin matrix.