Deionized Water: Water purified by removing highly active ions especially positively charged cations like calcium (Ca++) magnesium (MG++) and iron (Fe++) and (Fe+++).

Demand: Term used to describe the effect skin care products have on moisturization. A high demand indicates a need to reapply the product often.

Demineralized Water: Water run through active resin beds to remove metallic ions and filtered through a sub micron filter to remove suspended impurities. See Deionized Water.

Demulcent: Soothing, coating herbs that can protect irritated or inflamed tissue.

Deodorant: A product used to counteract body odors caused sweat. A deodorant containing antiseptic substances to kill bacteria and strong fragrances to mask offensive smells but it should not be confused with antiperspirants that actually inhibits the production of sweat.

Deoxyribonucleic acid: See DNA.

Depilate: Removal of hair on the surface of the skin. Examples include shaving or the use of depilatory creams.

Depilatory: A depilatory is a chemical sulfide that dissolves hair in the follicle. It also removes the outermost cells of the epidermis skin layer that leaves skin smoother. It has a more lasting effect than shaving (slower hair regrowth).

Dermabrasion: A procedure in which the skin is sanded to improve its texture. Microdermabrasion uses a type of sand to abrade the skin, usually done by an esthetician or a cosmetic doctor.

Dermal: Related to skin.

Dermal Papilla: Projection from the dermis that extends upward into the epidermis. The Dermal Papilla helps anchor the epidermis and dermis.

Dermatitis: Any inflammation of the skin. The reason may be a bacterium, fungus, or parasite; it can also be a foreign substance like an allergen. See Contact Dermatitis.

Dermatology: The study of the skin, its structures, functions, and diseases.

Dermatologist: A physician who specializes in the study of the skin, its structures, functions, and diseases (dermatology).

Dermatosis: A non-specific term used to denote any skin disease.

Dermis: The lower layers of the skin; the layers of skin beneath the epidermis.

Desquamation: The sloughing of dead corneocytes (cells located in the epidermis that are packed with fibrous protein called Keratin) from the horny cell layer of the epidermis (stratum corneum). The final stage in the ongoing cycle of skin cell birth, maturation, and death.

Detoxification: Process of ridding the body of toxins.

DHA: See Dihydroxyacetone.

Diaphoretic: Herb and/or substance that can assist in increasing capillary activity and sweating, which helps to release body toxins.

Diatomaceous Earth: A porous and pure form of silica formed from the fossil remains of algae. This form of each has great absorption power and can absorb up to four times its own weight in water. In masques it sets and gels on the skin’s surface.

Diazolidinyl: Cosmetic Preservative.

Dicaprate: Emulsifier (a thickening agent that helps bind different ingredients together).

Dicaprylate: Emulsifier (a thickening agent that helps bind different ingredients together).

Dicetyldimonium Chloride: A quaternary ammonium salt. Used often as a conditioning agent, compatible with surfactants and often used in shampoos.

Dihydroxyacetone (DHA): Obtained from glycerol, used to artificially tan skin. Reacts with amino acids in skin to provide a natural looking suntanned appearance. Usually derived from sugar cane, it causes the surface layer of the skin to oxidize.

Dilation: Enlargement of a cavity, canal, blood vessel, or opening.

Dimethicone: An organic silicone, used as a skin protectant and moisturizer. Well tolerated by even the most sensitive skins, dimethicone has a filming action on the skin surface which helps slow down moisture loss and further helps smooth fine, dry lines.

Dimethicone Copolyol: A Complex of natural silica that acts as a spreading agent for easy product application and also functions as a moisturizer. 

Dimethyl Lauramine Isostearate: Conditioning and thickening agent.

Dimethylol Dimethyl: See DMDM.

Dimethyl Stearamine: Conditioning and thickening agent.

Disinfectant: A product or ingredient that can help destroy microorganisms that cause infection.

Disodium Oleamide MEA-Sulfosuccinate: A wax-like solid surfactant (mixing agent) used as a solubilizer and wetting agent in bath preparations and lotions.

Diuretic: Something that can increase urine flow.

DL-Alpha Tocopheryl Acetate: Vitamin E acetate. See Vitamin E.

DMDM: (Dimethylol Dimethyl) Used with hydantoin to form a preservative. Slowly releases formaldehyde to give bactericidal properties to lotions.

DMDM Hydantoin: Preservative, antimicrobial to fight bacteria. 

DNA: The principle carrier or genetic information in all organisms.

DNA Enzyme Complex: Complex that has been bioengineered to supply the body with moisture and to help reduce the appearance of fine lines and wrinkles.

Dong Quai: An herb used to treat symptoms associated with menopause and menstrual irregularity.

Double Process: A two-step hair coloring process; first the hair is lightened and second the new color is added.

Draining Sinus: An elongated, serious acne lesion that tunnels through the skin.

Draize test: An animal test used to determine the effects of different substances on the eye.

Dulse: Dried sea-plant powder added to water that helps rid the skin of toxins and boosts circulation.

Dystrophy: A condition in which there has been a malformation through an error.