Beauty Glossary: S

Salicylic acid - an antibacterial, skin softening ingredient that comes from willow bark. A main ingredient in beta-hydroxy acids, it helps exfoliate dry, flaky skin and prevent and heal blemishes.

Saponification - the process of making soap.

Sclerotherapy - the process of eradicating spider veins by injecting them with saline solution. It is performed in a dermatologist's office.

Seaweed - a mineral-rich plant used in facial masks and other skin care products.

Sebaceous glands - oil-producing glands attached to the hair follicles.

Sebum - the oil secreted onto the skin from the sebaceous glands.

Shea butter (karite) - a buttery emollient from the fruit of the African karite nut tree. An extremely effective ingredient in moisturizers, shampoos, and conditioners.

Shelf life - the amount of time a product will remain fresh after it is opened.

Silica - a mineral used in face and body powders and facial masks to absorb oil and make them feel slippery.

Silicones - inert, nonreactive substances derived from silica or sand, they are popular in hair styling aids and, at one time, were used in breast implants. They are the words with a "-cone" ending on ingredients labels; examples are dimethicone and cyclomethicone.

Silk amino acids - used in hair sprays and as a hair and skin conditioner.

Sodium cocoate - an alkali used in soap.

Sodium hydroxide - lye used in hair relaxers and soaps.

Sodium lactate - a pH adjuster.

Sodium laurel sulfate - one of the most common, and most irritating, of all detergents, it is widely used in bubble baths, shampoos, cleansers, and shower gels. It's less irritating when combined with cocoamidopropyl betaine or sodium lauroyl sarcosinate, as it often is in shampoos.

Sodium laureth sulfate - a detergent used in cleansers and shampoos that is more gentle than sodium lauryl sulfate.

Sodium lauryl sulfate - a harsh detergent used in cleansers and shampoos.

Sodium PCA - a humectant and emollient.

Sodium tallowate - lard used to make soap.

Sorbitol - an alcohol used in cosmetics as a humectant.

Spirulina - algae rich in proteins and antioxidants that are used in algotherapy.

Squalene a rich emollient that penetrates extremely well into the skin. It is derived from shark liver oil and is also found in olive oil and wheat germ oil.

Stearic acid - a fatty acid used as a cosmetic base and emollient.

Stearyl alcohol - an emollient emulsifier.

Stratum corneum - the uppermost layer of the skin.

Subcutaneous - under the skin.

Sugaring - a method of hair removal similar to waxing, but the depilatory used is a mixture of sugar and honey. It is more expensive and time-consuming than waxing, but gentler and less painful.

Sulfur - an element used in anti-acne products.

Sun Protection Factor (SPF) - the number tells you the amount of time it will take your skin to burn with sunscreen compared to the amount of time before you'd burn with no sunscreen. (In other words, an SPF of 8 means you can stay in the sun 8 times as long as you could with no protection on your skin before your skin begins to burn.)

Superoxide dismutase - an enzyme used in skin care products.

Surfactants - detergents that act on the hair or skin to emulsify, lift, and remove dirt; usually more than one is present in a product because they need buffering; some examples include ammonium laureth sulfate, ammonium lauryl sulfate, cocoamide MEA, cocoamidopropyi betaine, cocoamphodiacetate, sodium laurel sulfate, sodium lauryl sulfate, sodium laureth sulfate, and sodium lauroyl sarcosinate.

Sweet almond oil - this soothing, highly absorptive oil from the kernel of the almond is a very effective moisturizer for the skin and hair.