Polyquaternium-10 – is it safe?
What is polyquaternium-10?
In our first post about conditioning ingredients, we will tell you about the benefits of polyquaternium-10 (PQ10). PQ10 is basically cellulose that has been reacted a couple different ways. Cellulose comes from plants, and it’s also the most abundant polymer found in nature! How about that? The precursor to polyquaternium-10 is hydroxyethyl cellulose (HEC). HEC is used in a wide variety of applications from paints, coatings, drugs, household products, and also cosmetics. It’s a thickener and it also helps binding materials together. In paints, it helps the paint coat the wall completely.
When HEC is quaternized to make polyquaternium-10, it has the added benefit of being attracted to damaged parts of the hair where you need it most. Damaged hair is hard to comb, so adding PQ-10 to those parts improves combability and feel of the hair to the touch. It’s basically a seeking missile that will destroy your bad hair day! For more information on frizzy hair, go back and read our early post on the topic here.
Is polyquaternium-10 safe?
There isn’t a CIR report I could find to link on this product, but it’s been very heavily studied for cosmetic use for several decades. There is a report that can be found here. It puts the conclusions on the page but there is a full report available with all the data in a link on the page (it’s not free). If you want the bottom line here’s the conclusion. PQ-10 was neither an irritant nor a human sensitizer when tested at 2.0%. Cosmetic products containing up to 1% PQ-10 were not human irritants, sensitizers, or photosensitizers. On the basis of the information presented, it is concluded that PQ-10 is safe as a cosmetic ingredient in the present practices of use.
You would almost never have a good reason to use PQ-10 above 1% in a formulation. I’ve never seen it used above that amount in all my years formulating. It would probably make the formula a bit too sticky and unpleasant at high levels like that. The data show it’s commpletely safe.
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It seems there are a million different polyquaterniums out there. What makes 10 different from the rest?
Polyquaterniums are polymers which have multiple cationic (positively charged) sections on the molecule. But other than that, they are not the same. They differ in molecular weight, side chain composition and how they interact with hair, skin and the formula. Polyquaternium 10 is particularly good at binding to hair when delivered from a shampoo. Other polyquaterniums do not adhere as well which is why we didn’t use them.