In general, silicones work by covering hair with a thin, hydrophobic (waterproof) coating. This coating serves several purposes: It helps reduce the porosity of the hair, which makes it less likely to absorb humidity; it helps reduce moisture loss from the inside of the hair; and it lubricates the surface of the hair so it feels smoother and can be combed more easily.
PROPERTIES OF SILICONES
The properties vary depending on which silicone is in the formula. Some silicones leave a heavy coating on the hair that can be hard to wash off. Others are very water-soluble and don’t build up at all. Dimethicone (sometimes called simethicone), for example, is the heaviest of all silicones used for hair care. It provides the most smoothing effect, but it is also the hardest to wash out. Cyclomethicone, on the other hand, gives a great slippery feeling while you’re rinsing your hair, but it evaporates quickly, leaving nothing behind.
Some natural oils are effective conditioners. Coconut oil, for example, doesn’t provide the same surface smoothing as silicones, but it has been shown to penetrate hair and plasticize the cortex, making hair stronger. (This isn’t true of all natural oils, however.) So oils are useful ingredients, but they’re not direct replacements for silicones.
THE BOTTOM LINE
It’s tough to tell which silicones are the best simply from reading the label because there are so many types of silicones and they can be used in combination with each other. You can’t simply say that all silicones are bad. Some women will find silicones too heavy for their hair; others will love the soft, conditioned feel they provide. You have to experiment to find what’s right for you.
WHAT’S THE DIFFERENCE BETWEEN A SILICONE AND A POLYQUAT?
Jackie just needs to know: What’s the difference between a silicone and a polyquat? Do both coat and stay on the hair? Do they both need to be removed by sulfates? Do they both tend to build up on the hair?
Silicones and polyquats are ingredients found in both shampoos and conditioners. They are put in formulas to offset the drying effects of detergents, improving hair by making it easier to comb, making it feel softer, increasing shine and reducing static flyaway. They really are amazing materials. The primary difference between them is their chemical composition and the way they stay on the hair.
**Caution: Science talk coming up …
SILICONES ARE MADE OF SILICON
Silicones (or “cones”) are molecules that have silicon in them. The silicone, which is typically derived from sand, reacts with oxygen, carbon and hydrogen to make useful materials. Ingredients like dimethicone and cyclomethicone are naturally slippery and shiny, which is why they are excellent for hair.
POLYQUATS ARE MADE OF HYDROCARBONS
Polyquats are molecules that are composed primarily of carbon, hydrogen and nitrogen. The quat part refers to the fact that they contain a positively charged nitrogen atom and the poly part refers to the fact that they are polymers. They also have a slippery effect and can smooth hair while reducing static charge.
BOTH STAY ON HAIR, BUT IN DIFFERENT WAYS
Because of the different chemistry of polyquats and silicones, each of these compounds uses a different method to stay on the hair. On hair, the damaged portions are typically negatively charged. The positive charges on the polyquat allow it to stick to these negative sites on the hair. It is a bit like two magnets being attracted to each other.
Silicones are not usually charged, but stay on the hair because of their incompatibility with water. If you put a drop of silicone in water, it will not dissolve, no matter how much you stir it. When a silicone product is put on your hair, it deposits and resists being washed off.
DETERGENTS ARE NEEDED TO REMOVE THEM
Since silicones and polyquats stick to hair, they need more than just water to remove them. In fact, silicones can stick to hair so well that they may require multiple shampooings before they are removed. Similarly, some polyquats may be difficult to remove from hair. While a sulfate shampoo isn’t required to remove them, sulfates are your best bet.
BOTH MAY BUILD UP ON HAIR
Depending on the type of molecule, both silicones and polyquats may build up on your hair. Dimethicone is one of the most difficult silicones to remove and multiple use of products with it can make your hair look dull and weighed down over time. Cyclomethicone, on the other hand, evaporates from hair like water and will not cause the same problems. Polyquats do not build up as much, but still require occasional washing with a polyquat-free shampoo.
THE BOTTOM LINE
Silicones and polyquats are different materials but they both stay on hair and can build up over time. It is a good idea to wash your hair once a week with a shampoo that doesn’t contain either one in order to prevent buildup and keep your hair looking fresh, shiny and manageable.
WHY DOES SILICONE BUILD UP ON HAIR?
When it comes to buildup, the type of silicone (and how much is used) is more important than if it’s used in a leave-on styler or a rinse-off conditioner. There are many types of silicone with scientific names that can be confusing, so let’s look at a few common examples.
NO BUILDUP
One of the most common types of silicone is called “cyclic” because the chain of silicone atoms that composes this kind is linked together in a ring structure. This type of silicone evaporates and won’t build up on your hair at all. It gives a silky-smooth feel and leaves the hair with incredible slip when wet. It’s used in both leave-on stylers and rinse-off conditioners and is commonly called cyclomethicone or cyclopentasiloxane.
VERY LITTLE BUILDUP
Another type of silicone is designed to be water-soluble. This kind provides very light conditioning and is unlikely to build up because it washes away easily with water. It is often used in conditioning shampoos. Look for polyol in the name, as in dimethicone copolyol.
MODERATE TO HEAVY BUILDUP
There is a different kind of silicone that is chemically modified to stick to your hair better. That means it conditions well, but it can also be more challenging to remove. This kind generally has amo, amine or amino somewhere in the name. For example, amodimethicone is commonly used in leave-in conditioners.
POTENTIALLY HEAVY BUILDUP
Finally, perhaps the most powerful type of silicone is referred to as a silicone oil. It comes in many different forms but is typically used at very high molecular weights to make it highly waterproof, so it provides good shine to the hair. Because it’s so water-insoluble, it can be very tough to wash off, depending, of course, on how much you have on your hair. Typically, this is used in rinse-off products. Look for it on the ingredients list as dimethicone.
IS BABY SHAMPOO GOOD FOR ADULT HAIR?
Sylvia asks: Are baby shampoos sufficient to clean adult hair? I know they are sulfate-free and I have been looking for this type of shampoo to minimize the drying effect from shampoos with sulfates.
There is a lot of misinformation out there about sodium lauryl sulfate (SLS) and shampoo.