Silicones in Hair Care: Why The Bad Rap?
What Are Silicones & Their Purpose?
Silicones can be found in shampoos, conditioners, leave-in conditioners, hair serums and masks because of their effectiveness at getting rid of frizz. Silicones are a stronger, organic/inorganic version of hair oil, though much more effective.
They function as powerful emollients and occlusives. Emollients soften and add shine, while occlusives are used to seal and lock in moisture and lock out humidity and frizz. Silicones do both of these really well.
Furthermore, silicones help provide slip so you can run your fingers and brushes through your hair with minimal tangling. All this sounds really good, right? So what’s the problem?
Before we can address the claims outlined above we need a better understanding of silicones.
The claim “all silicones cause buildup” is false. The more accurate claim should be, some silicones cause build up, while some are water-soluble, and some actually evaporate on their own. It all comes down to chemistry, and with most things in chemistry, it’s never black & white.
There are many different types of silicones but for simplicity we’ll divide silicone ingredients into three categories: water-soluble, water-insoluble, & evaporating. In the graphic below you’ll see many of the most common silicones.
In the first column we have what’s commonly referred to as PEG silicones. Since water is polar and oils are non-polar, they don’t mix or dissolve in each other, thus the potential for buildup. However by adding a polar substance like polyethylene glycol, you can make it water-soluble.
This doesn’t mean they will rinse out completely, but the PEG attached to it will significantly reduce buildup while still allowing the silicone to perform its job. These silicones will partially rinse out and partially stay on your hair to perform their occlusive magic.
One thing to pay attention to is the number next to the PEG or PPG. The higher the number, the more soluble it is. Anything under PEG-8 is not very soluble, while PEG-12 is more soluble, and PEG-16 even more soluble, and so on.
Next, in column two, we have the water-insoluble silicones which are the original version of the PEG-modified silicones you see in column one. These are the strong ones that will stick to your hair but do a great job of adding slip, shine, and fighting frizz.
You will see I starred amodimethicone in the middle. This one is supposed to be a special case. It’s a polymer-type silicone that binds to damaged parts of your hair and doesn’t accumulate on top of itself. However, other silicones can build up on top of it.
Finally in column three we have a special group of silicones that evaporate on their own. You commonly see these evaporating silicones mixed into products to help spread other ingredients throughout your hair. You might see an evaporating silicone added to a coconut oil serum to help spread it through your hair and then evaporate.
You will find these in hair serums and leave-in conditioners. They temporarily provide the detangling and slip so you can spread the product through your hair, and then evaporate. Any remaining residue can be removed with any shampoo.
How Much Silicone Buildup is Bad?
In a 1994 article in Skin Pharmacology and Physiology by Rushton, there were some interesting findings on silicones.
First, silicones from a 2-in-1 shampoo accumulated on the surface of the hair for the first five uses, but after that, there was no more accumulation. There is only so much surface on the hair for silicone to bond to, it does not accumulate indefinitely (1).
Second, 90% of silicone residue was removed with one shampooing with a silicone-free shampoo. The detergents sodium lauryl or sodium laureth sulfate, ammonium lauryl or laureth sulfate and cocamidopropyl betaine (possible coco betaine) are most effective in removing silicone residue (1).
Also, I’d say most buildup happens with styling products like hair serums, curl creams, and leave-in conditioners. Many of these products are very silicone-heavy (i.e. silicones are the first or second ingredient). If your shampoo & conditioner have silicones and you combine these with leave-ins with more silicones, you’re likely to see some buildup relatively quickly.
How Do You Get Rid Of Silicone Buildup?
Let’s say you do use silicones or notice silicones in your hair products. How do you get rid of the buildup? There is a common belief that only sulfates are strong enough to get rid of silicone build-up. As the journal said, sulfates are the quickest way to get rid of silicone build-up, but not the only way.
You can also use milder anionic surfactants that are combined with each other. If you don’t know what that means, here is a chart showing you the ingredients.
In the first column you have the strongest anionic surfactants, which are sulfates. In the third column are sulfonates, which are not as strong as a sulfate, but still strong. Any of these will do the job on their own.
But let’s say you want to get rid of silicones while staying sulfate-free. Then you can look at any of the ingredients from the middle column of mild anionic surfactants combined with each other or with the amphoteric surfactants in column three.
The good news is, most shampoos that are sulfate-free will combine 1-2 surfactants in them to still cleanse, meaning you can remove silicone buildup without sulfates.
The Verdict On Silicones in Hair Care Products
First of all, I think we can put to rest the idea that “if it ends in ‘cone,’ leave it alone.” In my opinion, silicones only become a problem with excessive buildup. One layer of silicones can be really helpful in your weekly hair regimen.
With that said, individuals with certain hair and scalp types or specific preferences might be better off avoiding silicones.
For example, if you have curly hair and follow the curly girl method to a T (which calls for not using any shampoo at all), or if you’re someone who subscribes to, “never use shampoo ever” (“no-poo”), and you only do conditioner washes (“co-wash”), then silicones will be hard to remove and should be avoided.
If you have super fine and thin hair, silicones could weigh your hair down with buildup. And if silicones make your hair look too shiny and you don’t like that, you might be better off without them.
For everyone else, I wouldn’t worry about it. Silicones are amazing at fighting humidity and frizz, they prevent breakage by adding slip, and they will come out easily with almost any silicone-free shampoo.
Silicone usage is less about harm and more about personal preference. They’re safe! It’s not something to freak out about and they can have tons of benefits.
- Rushton H, Gummer C, L, Flasch H: 2-in-1 Shampoo Technology: State-of-the-Art Shampoo and Conditioner in One. Skin Pharmacol Physiol 1994;7:78-83. doi: 10.1159/000211278 - https://www.karger.com/Article/Abstract/211278
- Ws, W. (1970, January 01). Silicone Ingredient Solubility List. Retrieved December 07, 2020, from http://science-yhairblog.blogspot.com/2014/04/silicone-ingredient-solubility-list.html
Founder of Mannered Manes, Travis is a men’s style & grooming expert with a passion for helping guys look & feel their best—inside and out. Life and hair growth is a journey, and you’re most fulfilled when you’re always growing.
See all Trav’s guest posts for The Longhairs.