Silicone & Skin Care

One of the most common and poorly misunderstood ingredients in the world of skin care is silicone. It’s nearly impossible to find a moisturizer, anti-aging formulation, makeup, foundation or even hair care product that doesn’t contain it. Since its invention in the 1950’s, it’s been prized by cosmetic formulators and consumers for its soft velvety texture, smooth tactile quality, ability to protect the hair cuticle, waterproofing properties and ability to improve the application of products, allowing them to be applied with a frictionless feel with no greasy or oily sensation.

Silicones are highly processed chemicals derived from silica, a blend of silicon (the 14th element on the periodic table and NOT the same thing as silicone!) and oxygen, the 2 most abundant elements on earth, which together form nearly 60 percent the planet’s crust. Silica, also known as silicon dioxide, is a common constituent of sand quartz crystals and is widely used in the production of glass.

There is no one ingredient called “silicone”. Rather silicones are a family of molecules that come in numerous forms, all of which are inert chemicals, structured like a chain made up of repeating units of links called “siloxanes”, substances that are similar to water, except for the substitution of an atom of hydrogen with an atom of silicon. The net result is a siloxane molecule (technically Si2O instead of H20), that has the liquidy qualities of water with a different characteristic feel. This feature of being water-like, with a distinct and highly unique texture, is what gives silicone its multifunctional characteristics and is the main reason for its ubiquity in the world of cosmetic formulations.

For the most part, you can tell a silicone chemical by the suffix “-cone”, the classic example being the two most common varieties, dimethicone, the first of the cosmetic silicones and cyclomethicone, which was developed more recently and functions as a lighter, more volatile version of its older cousin. An advanced version of the popular ingredient is the silicone gel, also known as the “elastomer”, which provides the classic silicone feel with a more solid nature and can be used to give products substance and body. Many hair care gels and shine agents take advantage of the thickening, as well as the shine enhancing properties of the silicone elastomers.

One of the most common uses of silicone is as pigment dispersants in foundations and blushes, which are designed to temporarily enhance skin appearance by covering imperfections and improving tone. Because of the importance of “spreadability” and ease of application, these types of products, which typically utilize iron oxide to achieve appropriate tint, will exploit the powers of silicone to allow the pigments to be delivered to the skin in a uniform fashion and create an even coating of color.

In addition to the delivery of tinted pigments, silicone based formulations can also be utilized for the application of non-colored particles, that can improve the appearance of fine lines and wrinkles. These solid substances allow formulations to simulate the appearance of flawless youthful skin by reducing or softening the effects of reflected light. Formulators call this a “soft focus effect”, after the photographic technique where a defective camera lens is intentionally used to create images with reduced detail. In cosmetics, a similar effect can be achieved by introducing particles into the formulation, dispersing or scattering light to optically blur the skin, improving the look of textural imperfections.

Another formulation issue that concerns a homogenous dispersion of particles involves sun protection. There are two types of ingredients that can be used to mitigate the damaging and aging effects of solar radiation. The first are called “organics” (e.g. octyl methoxy cinnamate, octyl salicylate), chemicals which are usually liquids. They readily dissolve into formulations and are thus favored by most cosmetic designers. Unfortunately, many of these substances have a potentially toxic profile and what the formulator gains with ease, the consumer may lose in terms of long-term safety. The second type of ingredient (e.g. zinc oxide and titanium dioxide), are solids called “inorganics”. While generally non-toxic, they are more difficult to disperse in products and are trickier to design. Because of the importance of complete skin coverage, formulators must create products that deliver the sun-protecting chemicals in an even and consistent layer, to assure complete protection against ultraviolet radiation. Additionally, the product must adhere to the skin over time and not be removed when the skin is brushed against other surfaces or exposed to water. By blending inorganic pigments into silicone, its waterproofing and adhesion properties can be exploited to create a more effective formulation and uniform dispersions can be created, assuring an even application of the sun blocking ingredients.

Perhaps the most common use of silicone ingredients is in hair care products. The same quality that can help silicone glide on the skin and creates the pleasant feel, allows them to form a coat on the hair shaft and lubricate strands reducing the formation of tangles. Silicone also reflects light, creating a shine and gloss effect that women (and men) love. Silicones can help protect hair from the thermal damage that can be caused by blow dryers and curling irons. Some silicones are marketed to formulators and consumers for their ability increase color absorption and retention of hair dyes.

Although FDA approved and generally considered as safe, there is a lot of mythology about the negative effects of silicones. There are some who think that they can clog pores and cause irritations and allergic reactions. While others believe that silicone can coat the skin, trapping bacteria and skin oils, leading to blemishes. The fact is, however, that silicones coat the skin much less than the waxes and most of the thickeners found in the majority of skin care products, because silicones are, from a molecular standpoint, too large to enter into and clog pores. As far as allergenicity and irritations go, you can chalk that up to misinformation too. Silicone containing products are so inert and non-allergenic, that they are used in medical tubes, catheters and adhesives in doctor’s offices and hospital settings, because they are so unlikely to cause reactions.

Recently some have asserted that silicones are non-biodegradable and may be an environmental hazard. Once again this belief is scientifically inaccurate. Research has shown silicones to be ecologically inert and they effectively breakdown and degrade to natural compounds of silicon dioxide (sand), carbon dioxide and water. Silicones entering water treatment facilities become adsorbed into the sludge and are effectively eliminated. While tests on living organisms have revealed no adverse effects or bioaccumulation.