Silicones consiste of two basic elements linked together, silicon and oxygen, and work by covering hair with a thin waterproof, but breathable, coating. They provide slip, making hair easier to detangle; reduce the porosity of the hair, making it less likely to absorb humidity; reduce moisture loss from the inside of the hair; control frizz; lubricate the surface of the hair to prevent breakage; add shine; create a protective layer that traps moisture in the hair; and seal the hair, helping protect hair color from fading and making it easier to style.
While silicones have been maligned lately in the name of “green beauty,” much of the fear surrounding them is unfounded. Many teach that silicones build up even just after a few uses, and that they build up so much over time that they eventually block moisture from being absorbed by the hair, creating brittleness. In reality, silicones don’t keep building up indefinitely (unless you never clean your hair), and probably wouldn’t even build up enough to reach the moisture-blocking point. Some have stated that silicones are toxic, when in fact they are inert, hypoallergenic and nonreactive.
There are also myths about silicone’s environmental dangers. It’s true that silicones are not biodegradable, but that’s not necessarily a bad thing. Glass, for example, is not biodegradable, but it is inert and nontoxic. While silicones aren’t biodegradable, they are degradable, meaning they revert back to silica (sand), carbon dioxide and water over time. This is very different from the environmental consequences of plastics, such as the microbeads used in many cosmetic scrubs. World-wide concentrations of silicones are low, even though silicones have been used by many industries for a very long time, suggesting that silicones are not building up in the environment.
So, I hope this has shed some light on the true nature of silicones and how they can help your hair look and feel its best!