Bella begs to know…I recently read on Eco-Chick and a couple of other places that adding a little baking soda to shampoo can help get rid of styling residue and other gunk in your hair. How does this work? Is it safe for hair?
The Right Brain responds:
Adding baking soda to shampoo is a very persistent beauty myth. Using baking soda as a shampoo substitute (i.e., as a dry shampoo) does make some sense because the powder can absorb oil and some surface dirt. But will adding baking soda to shampoo really result in better cleansing? There are three potential reasons why this might work:
3 Ways Baking Soda MIGHT Clean Your Hair
Enhanced detergency
Detergents, which belong to a chemical classification known as surfactants, work because they have both oil and water soluble properties. Baking soda, on the other hand, is a water soluble salt which doesn’t really have provide any detergency. You can easily demonstrate this by dissolving some in water and adding a drop of oil. If the baking soda was good at washing away oil it would disperse the oil droplet. (But it doesn’t.)
Increased abrasion
If you had some very insoluble substance stuck in your hair that shampoo would not remove, like chewing gum, the gritty texture of baking soda might help physically abrade it. But for the common types of soil that you will find in your hair (sebum and styling residue) you don’t need this increased abrasion.
Raising the pH to dissolve styling residue
At first glance this approach potentially makes the most sense. Styling polymers are neutralized with acid to make them less water-soluble (that’s why they can hold your hair in high humidity.) One way to get rid of styling gunk is to make it more soluble by raising the pH. Since the pH of a baking soda solution is about 9 this could work, right?
That, as they say, is a testable proposition. So we added a 1/8 teaspoon of baking soda to 1/2 ounce of the shampoo we’re currently testing (the new Mark Anthony Oil of Morocco Argan Oil shampoo.) Then we measured the pH using litmus strips.
As you can see from the strip on the left, the initial pH is pretty close to 7 which is neutral. After adding a good slug of baking soda the pH strip turned slightly darker. The lighting in the picture makes it hard to tell, but it looks like it went up to about 8 or 8.5. Unfortunately, this much of a pH increase won’t provide much cleaning boost to the shampoo because baking soda is a weak base and it won’t do a very good job of neutralizing the weak acids present in the styling resins.
The Beauty Brains bottom line
While adding baking soda to your shampoo won’t hurt your hair it also won’t help much. So if you like to do this and you think it gives you a little bit of an edge in cleaning power go for it. But, if you’re going to run out and buy a 50 gallon barrel of baking soda just because you think it’s critical for clean hair. then save your money.
Image credit: http://capl.washjeff.edu/2/l/5761.jpg
P.S. Did you like the way we slipped the mention of Marc Anthony Oil Of Morocco Argan Oil Shampoo