Silicones have gotten a lot of press recently in terms of the role they play in shampoo and conditioner. Many have cried that they cause build-up and breakage in hair when used over time, but silicones, like many cosmetic ingredients, simply aren’t that simple. While they don’t work for everyone, many people benefit from using silicones in hair products.
What Does Silicone Do in Hair Products?
Silicones coat the hair in order to make it smoother and shinier. They also help to stop water loss and humidity absorption. Consequently, using products with silicones improves both wet and dry hair brushing (Journal of the Society of Cosmetic Chemists).
Silicones also aid in strengthening hair. For example, dimethicone has been found 20,000 times better at reducing combing force on hair than distearyldimonium chloride (Handbook of Cosmetic Science and Technology). Silicones work well to protect against heat damage, protecting against damage and moisture loss (HAPPI).
Generally speaking, silicone attaches better to undamaged hair than to damaged hair. However, some forms of silicone, such as aminosilicones, adhere better to damaged hair (for example, dyed hair) (Hair Color: Research Update). However, aminosilicones diffuse light more in hair and thus lessens luster over time (Fibers and Polymers).
[Read More: Does Your Shampoo or Conditioner Really Matter?]
What Are the Downsides of Silicones?
Silicones can build up in hair, and those that are heavier are more difficult to wash out. In studies on 2-in-1 shampoo and conditioner, researchers found that dimethicone — one of the heaviest silicones — is mostly removed by washing (Skin Pharmacology and Physiology).
And having the commonly used cationic surfactants, quats — or quaternary ammonium compounds — helps to better deposit the silicone throughout the hair.
Cationic surfactants do similar things to damaged hair, helping to make combing and brushing easier and remove static (Journal of the Society of Cosmetic Chemists). However, cationic surfactants are positively charged, while hair is negatively charged, meaning that cationic surfactants bond more closely with hair and are more difficult to wash off than silicones alone.
How Do I Get Rid of Silicone Build-up?
You can remove build-up in hair using cleansers with Sodium or Ammonium Lauryl/Laureth Sulfate, Sodium C14-17 Alkyl Sulfonate (Olefin Sulfonate), or Cocoamidopropyl Betaine (Naturally Curly). Some of these, such as sodium lauryl sulfate, can be harsh on hair and an irritant for skin.
[Read More: Spotlight On: Sodium Lauryl Sulfate]
If you’re co-washing your hair, that is, using conditioner some days instead of a shampoo and conditioner combo, and you’re prone to silicone build-up, you should skip the silicone conditioner (at least on co-wash days). Also, if you have fine hair, silicones could weigh it down.
Inevitably, this is one of those times where something is neither good nor bad for everyone. Many people benefit from using silicones: they make hair smooth and shiny, they make it easier to brush, they inhibit water loss, etc. But some people don’t have these benefits: silicone builds up in their hair or otherwise weighs it down. The best way to find out whether silicones are right for you is to test silicone-containing and silicone-free shampoos to figure out what works for your individual needs.