via The Beauty Brains

Rae really wants to know…Hi, in your blog you talked about the 1% line. I’m not a cosmetic chemist and I kind of always wondered how to guestimate where the 1% line is. So my question is, if you’re not a cosmetic chemist, what’s a good guide to know more or less the ratio of an ingredient to the whole product?

The Right Brain responds:

This is a really tricky question because there is no single answer that covers all products. But we can give you a very rough, general rule of thumb to follow.

Ingredients in Cosmetics

The vast majority of cosmetic products are water based. These include emulsion products (oils mixed with water) like skin lotions and hair conditioners as well as surfactant products (detergents mixed with water) like body washes, shampoos and facial washes. In these product water, of course, will almost always be the first ingredient in the list. After that, the next 4 or 5 ingredients are usually the ones responsible for the primary functional properties of the product – in other words they are the cleansers that make it foam or the conditioners that make your hair and skin feel soft. The same principle applies to powder based products (like eyeshadow, foundation, and baby powder) as well as solvent based products (like water-free hairsprays and silicone shine sprays.) So the magic rule of thumb is the first 5 ingredients are the ones that matter the most. After the fifth ingredient everything else is probably below the 1% line. This is where a lot of “snake oil” ingredients hide.

The 1%

Now, before you start an “Occupy Cosmetics” movement to complain about the 1%, let me point out that this doesn’t mean that none of the ingredients below the 1% line matter. For example, pigments are used at very low levels yet they are critically important to color cosmetics. And preservatives are only used at a few tenths of percent, yet I wouldn’t want to buy a product without them! There are many exceptions to this “First Five” rule.

The Beauty Brains bottom line

This rule of thumb is about the best guideline we can give to help you guestimate the level of ingredients in cosmetics. But that’s just our humble opinion: If there are any other cosmetic scientists reading this post we’d love to hear if you have a different perspective. And if anyone has a question about a specific ingredient in a particular product, we’d be glad to help answer any questions. Just leave a comment on this post or start a thread our Forum.

CN Says-

I’ve always heard that the first 4 or 5 ingredients in a product are what matters. That’s why when a conditioner says, ‘now with Argan oil’ and it’s like the 15th ingredient, I pass. Many of my favorite and most effective conditioners have behentrimonium methosulfate and/or cetearyl alcohol as one of the top five ingredients.

Which ingredients do you look for in the top 5?