Beauty Glossary: I

Imidazolidinyl urea - after the parabens, the most commonly used preservative in cosmetics.

Infusion - herbs steeped in water. The resulting extract can be used as a cosmetic, a medicinal base, or a tea.

Ingrown hairs - hairs that point in instead of growing outward and become trapped beneath the skin. They can cause folliculitis.

Iron oxides - inert mineral compounds used to add colour to cosmetics.

Isopropyi lanolate - made from fatty acids of lanolin and an alcohol, it is used to improve penetration and smoothness of skin care products.

Isopropyi myristate - made from myristic acid and an alcohol, it is used in skin care products to soften the skin but can be comedogenic.

Isopropyi palmitate - made from palmitic acid and an alcohol, it is used in skin care products to soften the skin.

Jojoba oil - an excellent emollient for skin and hair that is obtained from the nut of the jojoba shrub, which is native to the North American desert.

Kalaya oil - an easily absorbed skin moisturizer that is a by-product of the Australian emu.

Kaolin - white clay widely used in facial masks; it takes on colour well and is also used as a base in powder, blush, foundation, and eye shadow.

Karite - shea butter.

Keratin - the protein that forms the base of human skin, hair, and nails.

Keratosis pilaris (KP) - a chronic, hereditary skin condition that manifests itself as swaths of hard, pimplelike bumps, without redness or irritation. KP most often appears on the backs of the upper arms, buttocks, and outer thighs.

Kojic acid - a skin lightener used in cosmetics to fade brown spots.