How do clarifying shampoos work?

Noumenon needs to know…How exactly do clarifying shampoos work? Some say that the extra-harsh Lauryl surfactants are what strips the hair of all the build-up, and they are safe to use once in a while for clarifying purposes. However, others say that it has nothing to do with the strength of the surfactant and even Sodium Laureth Sulfate can be used in a clarifying shampoo on it’s own. These people tend to claim that it’s something like lemon peel or an acidifier like citric acid that helps to strip the build-up. Could you please help to “clarify” the situation for us all? What exactly is the specific ingredient(s) that removes build-up beyond my gentle Sodium Laureth Sulfate based shampoo? Or is the whole clarifying thing a myth and you can really use any shampoo you want to remove build-up equally?

The Right Brain clears up clarifying:

There seems to be a popular misconception that clarifying shampoos work by using acid to remove hard water scale – kind of like “Lime-Away.” WiseGeek and both claim that acetic acid should be a major component in a clarifying shampoo but the Beauty Brains have never seen a shampoo actually formulated that way.

Acid washed

I can see how this idea got started because it goes along with the notion that using vinegar to rinse your hair closes the cuticle and makes hair shinier. Unfortunately hair biology is not that simple. It’s true that very high pH chemical treatments (like relaxers) swell the hair shaft and lift the cuticle.When you relax your hair, you do need to neutralize the high pH so in that case acid treatment makes sense. But the same principle doesn’t really apply to hair that hasn’t been freshly relaxed or permed.

Real cause of build up

Hard water residue is not even the most common cause of build up. It’s more likely to be a result of not properly removing styling products. And if that’s the cause, then you certainly don’t want to use a product that contains more acid. That’s because the styling resins used in hairsprays, mousses, and gels become more water soluble when the pH is raised. So to help get rid of styling resin buildup you want to use a product that with a higher pH not lower which us what acid would do. Another possibility is that build up is caused by high molecular weight silicones and other water insoluble oils that deposit on your hair form conditioners or treatments. Neither acid or base will get rid of those bad boys.

The real clarifier

So what ingredients are really responsible for clarifying? Our old friends surfactants! A lot of people won’t want to hear this, but the lauryl sulfate type of surfactants are among the safest most powerful cleansers you can buy. As we explained in The Danger of Clarifying Shampoos, some people do complain of dry itchy scalp after using sulfate shampoos especially in dry climates. But most people have no problem, especially if they use them infequently.

A typical sulfate shampoo: Tresemme Deep Cleansing Shampoo

If sulfates just aren’t your cup of tea, there are plenty of other surfactants to choose from. Non-sulfate anionic cleansers include Sodium Lauryl Sulfoacetate, Disodium Laureth Sulfosuccinate, Sodium Cocoyl Isethionate, Sodium Lauryl. These tend to be less stripping so you may find they don’t clarify as well.

Nonsulfate anionic shampoo: Pureology Serious Colour Care Pure Volume Shampoo

Finally you can use an amphoteric shampoo, like a baby shampoo, which primarily contain milder amphoteric surfactants like PEG 80 Sorbitan Laurate, Cocamidopropyl Betaine, Lauroamphoglycinate. Those generally provide the least cleansing.

Amphoteric shampoo: Johnson’s Baby Shampoo

Clarifier can’t condition

In addition to choosing the correct type of cleansing ingredients it’s very important to choose a clarifying shampoo that doesn’t contain any conditioning agents. You want to make sure that you’re removing gunk from your hair, not depositing more stuff. So avoid any “”cones” like dimethicone, cyclomethicone, or amodimethicone and any conditioning polymers like guar hydroxypropyltrimonium chloride and Polyquaternium 7 and 10.

The Beauty Brains bottom line

Clarifying shampoos work by washing away the gunk that’s built up on your hair. You don’t need any fancy product to do that – a simple, non-conditioning shampoo will do just fine for most people.

What do YOU think? Do you have a favorite deep cleaning shampoo? Leave a clarifying comment for the rest of the Beauty Brains community.