Silicones are synthetic compounds that are made from silica, a group of minerals composed of silicon and oxygen. Silicone and silicon are two distinct entities, although many people confuse the two. Silicon (without the e) is the eighth most common element in the universe and is a component of sand, sandstone, dust and other natural materials. Silicone is made synthetically from silica, and silica is composed of silicon and oxygen.
To make silicone, silica is polymerized with other compounds including tetraethoxysilane and chlorsilanes. The final product is pure and typically doesn’t contain harmful contaminants or heavy metals. Silicones have a variety of textures and consistencies. Some are liquid or gelatinous while others are firm and feel like rubber or hard plastic.
Silicones have a large number of commercial applications and are a component in a variety of household and industrial products. Hardware stores sell tubes of silicone to create weatherproof, waterproof seals for pipes and other joints. In addition, silicone is used to form casings for electronic devices, as flame retardants, as lubricants, to insulate spark plugs, as defoamers and to seal aquarium joints. Silicone is also a component in home and kitchen products. For example, it’s used to make molds for molding candy, muffins and other food products, and food-grade silicone is used to make non-stick cookware. Silicone has the advantage of being stable even at high temperatures, and it’s resistant to stains.
Silicone also has a place in the medical world where it’s used to make implants, including breast implants and medical-surgical devices. It’s also used to make bandages and wound dressings. To be placed inside or on the body, silicones must be medical grade. Soft silicone dressings are used to cover wounds and protect them during the healing process, and silicone gel sheeting is used to reduce the risk of elevated scars or keloids after surgery.
Silicones are also ingredients in cosmetic and personal care products. They’re added to moisturizers and anti-aging skin care products because of their emollient or moisturizing properties and because they improve the “feel” of cosmetic products, giving them a silkier texture. One type of silicone called cyclomethicones act as solvents in cosmetic products. Silicones also increase the ability of pigments in cosmetics to spread over the skin so it gives cosmetic products more uniform coverage. This makes them a useful addition to makeup foundations and products formulated to cover blemishes. When they’re added to sunscreen products, sunscreen goes on more evenly. This increases the effectiveness of sunscreens by reducing “gaps” during sunscreen application and by keeping the product from rubbing off too easily.
Silicones in foundations and moisturizing products provide a thin but "breathable" layer over the skin that reduces moisture loss without feeling heavy. Contrary to popular belief, silicones don’t clog pores since they’re inert and can’t penetrate beneath the skin surface.
Silicones, including cyclomethicone, dimethicone, amodimethicone and diemthicone copolyol, are common ingredients in hair care products that are formulated to increase hair softness and shine. They do this by coating and sticking to the hair shaft. This fills in damaged areas, giving hair a smoother texture and the ability to reflect light better. They also reduce porosity and makes hair easier to manage.
Some people believe silicones in hair care products build up over time and can weigh hair down, causing it to feel greasy and look lifeless. One way to avoid this is to use products that contain light-weight, silicones that dissolve easily in water like dimethicone copolyol or cyclomethicone rather than heavier ones that are more likely to build-up like amodimethicone and dimethicone. Using a clarifying shampoo regularly also helps to reduce silicone build-up.
Is silicone in cosmetic and personal care products safe? Silicones are inert. Even though they’re made synthetically, they’re pure and shouldn’t be contaminated with heavy metals or other harmful ingredients. Since they’re inert, they don’t penetrate beneath the skin surface or enter the bloodstream. They also typically don’t cause skin irritation or allergic reactions. The FDA deems them to be safe in the quantities found in cosmetic and personal care products. Most allergies to silicone are related to other ingredients in the product – not silicone.