Another cosmetic ingredient to be afraid of

Lindsay’s looking for information:

What is quaternium/polyquaternium? If you have allergic contact dermatitis to quaternium-15 should you avoid contact with any other poly/quaternium numbers?

The Left Brain helps her out:

Quaternium and Polyquaternium (or “Quats” for short) are the names of CATEGORIES of chemicals. There are many different chemicals in each category. For example, there’s Quaternium 15, 18, 24, 27, 80 and Polyquaternium-6, 7, 10, 11, and 28 to name a few.

Quat doesn’t mean squat

Unfortunately, the name doesn’t really tell you anything about the chemical itself. The actual chemical name of Quaternium 15 is Methenamine 3-chloroallylochloride but it’s also known as 3,5,7-Triaza-1-azoniatricyclo(,7)decane, 1-(3-chloro-2-propenyl)-, chloride; N-(3-Chloroallyl)hexaminium chloride; and Hexamethylenetetramine chloroallyl chloride. You can see why we call it “Quaternium-15” for short!

Anyway, this particular quat is a preservative – it keeps bugs from growing in your cosmetics. It works by releasing formaldehyde, which probably explains your reaction to it. Other quats may have similar names, but that doesn’t mean they will react with your skin the same way. For example, Quaternium-18 is a long chain fatty conditioning agent and Quaternium-80 is a silicone based conditioner. The chemistry of these Quats is completely different from number 15.

The Beauty Brains bottom line

Not all Quats are created equal. Stay away from Quat-15 if you know it gives you problems but that doesn’t mean you have to shy away from the rest. I assume you’re not the only person with this question and it will be interesting to see if any companies begin offering “Quat-free” products. But so far, the “naturals” crowd don’t seem too worried about Quats. Jason Natural Cosmetics, for example, are pretty picky about their ingredients and they have an Apple and Green Tea shampoo that contains polyquats.

By the way, if you’re not sure if you have contact dermatitis or not, read our previous post on how to tell the difference between skin allergies and skin irritation.