Sulfates in Shampoo

2 minute read
Originally posted here: https://mcgill.ca/oss/article/did-you-know-general-science/sulfates-shampoo

As someone who likes to routinely dye my hair bright pinks, blues and purples, I’m often told by my hairdresser to use sulfate free shampoos. He often talks to me about how multiple bleachings and dying’s will leave my hair damaged and brittle, and how sulfate free shampoo will be gentler, both on my damaged hair and on the colour. It seems like every time I take a shower it occurs to me to look into why that is, and whether or not it’s true, but somehow by the time I’m dry, dressed and sitting at the computer I’ve forgotten again. Finally though, here is what I’ve found about sulfates in shampoos. 

Shampoo as we know it was invented somewhere near the 1920’s and 1930’s. It was in 1930 that Procter and Gamble made the first sulfate-based shampoo, and since then the formulations haven’t changed all that much. It’s important to remember that ‘sulfate’ isn’t one compound, it’s a common name for any compound containing a sulfate. The ones commonly used in shampoo (historically and currently) are sodium laureth sulfate, sodium lauryl sulfate, or ammonium laureth sulfate.

So what do sulfates do anyways? Well, a couple of things. Primarily they are surfactants, which means they can attract both water and oil molecules, and it’s this property that makes them good for cleaning. They attract the oil on your scalp, then wash away down the drain. It’s also their surfactant status that allows sulfates to create the lather we all know and love in our shampoos. 

The problems with sulfates really are that they’re a bit too good at their job as surfactants. Their ability to effectively strip dirt and oil out of our hair means that we also lose a lot of natural oils that protect our hair and scalp, which can leave our heads feeling dry, or even getting irritated and red if you have sensitive skin. Sulfates are also irritants, so if you get shampoo in your eyes a lot (like me), you may notice that sulfate containing shampoos sting a bit more. If you dye your hair (again, like me) you likely will want to use sulfate free shampoos, as sulfate’s efficacy at stripping oils will also strip colour. 

Outside of being a bit intense, there are no other problems with sulfates. The myth that they cause cancer is just that, a myth, and they have been studied and approved many times for use in hair products. Shampoos need surfactants to work (they’re made up of 5-30% surfactant), and sulfate-based surfactants are the most effective option getting the job done, but there are other options if you find these shampoos drying your skin out or causing rashes. Do not, however, buy into the media hype that normal shampoos are dangerous or unhealthy.

If You Have a Nut Allergy You Might Want to Check Your Shampoo Ingredients

Originally posted here: https://mcgill.ca/oss/article/you-asked/nut-allergies-and-shampoo

Nut allergies affect about 2% of the Canadian population and can be broken down into tree nut allergies (like almonds or cashews) and peanut allergies (peanuts aren’t actually nuts but legumes). These allergies are caused by ingesting or inhaling certain allergenic nut proteins, not all of which have been identified yet. So, if these proteins were present in oils made from nuts that are used in cosmetics like hand cream or shampoo, one could have a reaction to them.

If you’re allergic to peanuts, that’s likely all you’re allergic to. Numbers vary on the percentage of people allergic to peanuts that have cross-reactivity to other legumes like soy or tree nuts, but it’s not a majority. On the other hand, if you’re allergic to one kind of tree nut, chances are you’re allergic to several. You are likely, however, not allergic to coconut or nutmeg (though it’s a common misconception) as they are not nuts.

Studies have found that contact allergic reactions can occur due to exposure to allergens in cosmetics. But these reactions only occur if the relevant proteins are intact, so in general, the more processed and refined the cosmetic, the smaller the likelihood of a reaction.

Allergens in cosmetics can pop up more than you might expect. Peanut oil is often used under the name arachis hypogaea in shampoos and creams. Tree nut oils in cosmetics are downright common, with almond oilargan oil and shea butter being some common examples. Coconut oil is also growing in popularity lately, with many companies incorporating it into products in order to market them as ‘natural’. Looking in my bathroom I found six products containing peanut, tree nut or coconut oils.

Since every allergy is different it’s really best to evaluate your own situation. If you’re allergic to tree nuts but not coconut, look for coconut-based products. If you’re allergic to tree nuts and coconut, you might have to look for specialty products or make your own. Or, you might check the products you’ve already been using and realize that they contained your allergen, in which case you’re probably good to keep on using them.