Beauty Glossary: M

Magnesium aluminum silicate - a clay.

Magnesium laureth sulfate - a surfactant used in shampoos.

Marine extracts - mineral-rich ingredients derived from algae and/or seaweed that are used in skin care products and facial masks.

Melaleuca - tea tree oil.

Melanin - gives pigment to the skin.

Melanoma - the deadliest form of skin cancer, it is known as a "white-collar" disease because it most often afflicts people who spend the majority of their time indoors, and then expose themselves to intense bursts of UV radiation.

Menthol - the main element in essential oil of peppermint, it is used in body care products for its soothing properties.

Methacrylic acid - an acrylate used in nail polish that can be irritating to eyes, nose, and throat and can cause dizziness, shortness of breath, and asthma.

Methyl cyanide - an extremely toxic chemical found in many artificial nail removers. Its use should be avoided, especially by pregnant women.

Methyl paraben - a preservative.

Mineral oil - a clear, odorless petroleum-based oil, it is the most commonly used oil in cosmetics. People with oily skin should avoid it.

Nanocapsules - tiny lipid balls loaded with Vitamin E.

NaPCA (sodium PCA) - a humectant and emollient.

Neroli oil - extract from the flower of the sour orange tree; it is used in cologne, perfumes and aromatherapy.

Niosomes - compounds that claim to deliver moisture below the surface of the skin.

Noncomedogenic - does not clog pores.

Novospheres - liposomes with time-release action that moisturize the skin over a period of many hours.

Oat flour - derived from oats, it stops itching, binds moisture, and soothes skin.

Occlusive - a substance that is impenetrable; used as a barrier to hold in moisture.

Octyl methoxycinnamate - a sunscreen ingredient that can irritate the skin when worn for an extended period of time.

Oleic acid - an emollient and soap base derived from animal fats or vegetable oils.