Tea Tree Oil: A natural preservative with antiseptic and germicidal properties used in soaps, shampoos, and skin-care products.

Telangiectasia: A visible area of the skin in which the skin’s color is due to permanent enlarged superficial blood vessels.

Telogen: Resting phase of hair growth cycle.

Temporary Color: A hair color formula that lasts only until you shampoo your hair.

Teratogen: An agent capable of causing malformations in embryos (causes birth defects). Isotretinoin, the oral retinoid for acne, is a teratogen.

Teratogenic: Causing birth defects.

Terminal: The definition of a terminal, as it applies to cosmetics, is one of two types of hair shaft. The terminal hair shaft is thick, long and dark. The scalp, eyebrows, axillae and pubic regions are covered with terminal hairs.

Tester: A sample product available for testing (trying out).

Testosterone: The principal reproductive androgen of males, largely responsible for sexual maturation, some libido, and a range of metabolic reactions

Tetracycline: First of the broad-spectrum antibiotics. Used in oral and topical forms as an acne treatment. It blocks the binding of aminoacyl tRNA to the ribosomes of certain bacterium.

Tetrasodium EDTA: Same as sodium EDTA. It's a chelating agent (sequestrant – a remover/separator) that reacts with sodium, calcium and magnesium salts found in hard water and makes them water-soluble. Water softener. A bonding agent that links with minerals to prevent them from causing microbial growth.

Texturize: To comb relaxer through the hair and leave it in briefly to loosen the curl pattern.

Thea Sinensis Extract: See Green Tea.

Thiamine: (Vitamin B1) Plays a key role in helping the body generate energy; aids in the digestion of carbohydrates; is essential for the normal functioning of the nervous system, muscles heart; stabilizes the appetite; and promotes growth good muscle tone.

Thickening Mascara: A heavier mascara formula that builds up a volumizing coat of color on the lashes.

Threonine: (Essential Amino Acid) An important constituent of collagen, Elastin, and enamel protein. It is an important constituent in many body proteins and is necessary for the formation of tooth enamel protein, collagen and elastin. It is a precursor to the amino acids glycine and serine. It acts as a lipotropic in controlling fat build-up in the liver. May help combat mental illness and may be very useful in indigestion and intestinal malfunctions. Also, Threonine prevents excessive liver fat. Nutrients are more readily absorbed when threonine is present.

Thrush: Infection of the mouth or genital regions by the fungus Candida Albicans.

Thyme: Thyme is known as a powerful antiseptic and a general tonic, with healing powers. It is said to be used in cases of anemia, bronchial and intestinal disturbances. Properties and Uses (Garden thyme): Anthelmintic, antispasmodic, carminative, diaphoretic, expectorant, sedative. As a tincture, extract, or infusion, thyme is commonly used in throat and bronchial problems, including acute bronchitis, laryngitis, and whooping cough, and also for diarrhea, chronic gastritis, and lack of appetite. For coughs and spasmodic complaints, make the medication from the fresh plant. A warm infusion promotes perspiration and relieves flatulence and colic. Oil of thyme (thymol) has a powerful antiseptic action for which it is used in mouthwashes, toothpastes and soap. Thymol is also effective against ascarids and hookworms. As a local irritant, it can be used externally for warts or to encourage the flow of blood to the surface. Thyme baths are said to be helpful for neurasthenia, rheumatic problems, paralysis, bruises, swellings, and sprains. A salve made from thyme can be used for shingles.

Thymol: Oil of thyme (thymol) has a powerful antiseptic action for which it is used in mouthwashes, toothpastes and soap. Thymol is also effective against ascarids and hookworms. As a local irritant, it can be used externally for warts or to encourage the flow of blood to the surface. See Thyme.

Tincture: The term tincture (also called alcoholic tincture, and spirituous tincture) is reserved for the alcoholic solutions of nonvolatile substances, alcoholic solutions of volatile substances being called spirits. A solution (commonly colored) of medicinal substance in alcohol, usually more or less diluted.

Tinea Capitis: A fungal scalp infection (i.e., ringworm). Tineas: A dermatomycosis; any number of skin fungus infections, such as ringworm, athlete's foot, and so forth.

Tinted Moisturizer: A moisturizer that contains a bit of color.

Tissue Respiratory Factor: See TRF.

Titanium Dioxide: (Microcrystalline) Microcrystalline Titanium Dioxide is a new inorganic natural material, which functions as a sunblock to both UVA and UVB rays. A non-chemical, common agent used in sunscreen a product that works by physically blocking the sun. It may be used alone or in combination with other agents.

Tocopherol: (Vitamin E) Accumulates in the epidermis and forms a barrier against moisture evaporation from the skin. An anti-oxidant, Vitamin E helps prevent free radical damage in the skin tissues. Major anti-oxidant nutrient; retards cellular aging due to oxidation; aids in bringing nourishment to cells; strengthens the capillary walls prevents the red blood cells from destructive poisons. Aids against dry skin. Used as an antioxidant in cosmetics. See Vitamin E.

Tocopherol Acetate: (Vitamin E) Used in skincare products. Accumulates in the epidermis and forms a barrier against moisture evaporation from the skin. An anti-oxidant, Vitamin E helps prevent free radical damage in the skin tissues. Major anti-oxidant nutrient; retards cellular aging due to oxidation; aids in bringing nourishment to cells; strengthens the capillary walls prevents the red blood cells from destructive poisons. Aids against dry skin. See Vitamin E.

Tocopheryl Linoleate: (Vitamin E) A substance that helps prevent stiffening of the stratum corneum as a result of UV exposure. Provides the skin with linoleic acid, one of the major essential fatty acids. Accumulates in the epidermis and forms a barrier against moisture evaporation from the skin. An anti-oxidant, Vitamin E helps prevent free radical damage in the skin tissues. Major anti-oxidant nutrient; retards cellular aging due to oxidation; aids in bringing nourishment to cells; strengthens the capillary walls prevents the red blood cells from destructive poisons. Aids against dry skin. See Vitamin E.

Tocopheryl Nicotinnate: Increases blood supply at the skin's surface without irritation.

Toluene: Common solvent that is sometimes used in nail polish.

Tone: A hair or skin color’s underlying shade, which usually falls into one of three categories: warm, cool, or neutral.

Toner: Product that is used after cleansing to help return the skin to its natural pH. A toner helps remove dirt or debris from the skin.

Tonic: A substance taken to strengthen and prevent disease, especially chronic disease. Improves function of an organ or tissue. A product that nurtures enlivens and/or returns the normal tone to an organ or tissue (like skin).

Topical: Applied to the skin surface; applied externally.

Toxins: Any of a number of substances dangerous to life and overall health. The long-term effect of small amounts of toxins in food and cosmetics puts us at risk.

Trace Minerals: Play a major role in health, since even minute portions of them can powerfully affect health. They are essential in the assimilation and utilization of vitamins and other nutrients. They aid in digestion and provide the catalyst for many hormones, enzymes and essential body functions and reactions.

Transepidermal Water Loss: The migration of moisture upward through the skins tissues (from deeper dermal tissues). One of the sources of moisture for the stratum corneum.

Transparent Soap: Super fatted soap with a high glycerin content. Usually used for sensitive and normal-to-oily skin.

Tretinoin: Used as a topical treatment for the prevention and treatment of acne. A derivative of vitamin A

TRF: (Tissue Respiratory Factor) Skin care complex.   Composed of amino acids, mono- and disaccharides, vitamins, phosphorus containing compounds, nucleosides and nucleotides. TRF substances are produced by living cells (like yeast) upon injury. They may serve as healing agents, stimulate collagen and elastin production, and regenerate cells on the lower levels of the skin.

Trichologist: A professional who analyzes the hair and scalp to determine possible causes of hair problems.

Triclosan: An active broad-spectrum antibacterial agent that kills bacteria on the skin's surface. Shown to kill the bacteria associated with acne.

Trideceth-6: Emulsifier (thickening agent).

Triethanolamine: See TEA.

Triethyl Citrate: Derived from citric acid. It gives pliability to fixatives (fixatives may be decalcifying and/or hardening agents).

Triglyceride: Naturally occurring ester of fatty acids and glycerol; chief component of fats and oils. A type of blood fat. The body needs insulin to remove this type of fat from the blood.

Trisodium EDTA: A preservative; a sequestering (a removing/separating agent) and chelating agent (of sodium salt).

Trisodium Etidronate: A preservative.

Tyrosine: One of the twenty amino acids directly coded in proteins. Nonessential in humans since can be synthesized from phenylalanine. It is the amino acid from proteins that is converted through several metabolic steps to melanin. It is added to tanning accelerator products to supplement the body's normal level of tyrosine at the skin's pigment cell level thereby speeding the tanning process. Tyrosine is the amino acid in hair that color adheres to.

T-zone: The forehead, nose and chin areas, which tend to be oilier than the cheeks. Breakouts are most common in the T-zone.