Beauty Glossary: D

Dandruff - a form of dermatitis caused by an overgrowth of yeast that results in dryness, itchiness, and flaking. (It can afflict oily scalps as well as dry and normal ones.)

Deionized water - water that has been filtered and treated to remove metallic ions, kill microorganisms, and remove impurities.

Deodorant - a substance that masks offensive body odors.

Depilatory - cream used to melt away unwanted hair with calcium or sodium thioglycolate or sulfides. (These are the same ingredients used in permanent wave and
hair-relaxing solutions, but in stronger concentrations in depilatories.)

Dermatitis - skin inflammation accompanied by redness, itchiness, dryness, or cracking.

Dermis - the inner layer of the skin.

Developer - an oxidizing agent, usually hydrogen peroxide, that allows hair dye to take hold on the hair.

Diethanolamine (DEA) - a detergent, humectant, and solvent used in shampoos and
shower gels.

Dihydroxyacetone (DHA) - the active ingredient in self-tanners.

Dimethicone - a silicone oil used in hair and skin care products. Adds shine to the hair and a slippery feeling to skin products.

DMDM hydantoin - a preservative used in shampoos, conditioners, and creams that can irritate the skin and may release formaldehyde.

Dry Shampoo – usually consisting of a water-absorbent powder such as talc and a mild alkali; it is placed in the hair and then brushed out, carrying with it any dirt and oil.

Durvillea Antartica extract – an algae extract used in ant-aging products.