When it comes to hair washing, my modus operandi is pretty straightforward: Get into the shower, wet my entire head, apply shampoo all over, and rinse. Then, apply a conditioner or hair mask. The end.
A routine procedure, simple enough. Or, so I thought. Because as it turns out, I’ve actually been washing my hair all wrong. And, not just that—I’ve been using the wrong shampoo, too.
Mind-blowing information, at least for me. And maybe for you, too. It comes courtesy of Lena de Pons, a pharmacist based in Spain who just so happens to be an expert on the science of skin-, hair-, and scalp-care. She advocates for the importance of knowing how—and most importantly, with what—to wash our hair. And, she swears that the secret to getting what she calls “a hair glow” is actually all about the type of shampoo we’re using and not much more. Her main mane recommendation? Use a shampoo with an acidic pH in order to seal the cuticle and help reflect light.
How an acidic shampoo seals the cuticle to add shine
If a shampoo with an “acidic pH” sounds like it would fry your hair, it might be helpful to first get a baseline understanding the structure of your hair. “The hair cuticle is made up mainly of keratin; it is the outermost layer of the hair, and therefore the one that protects the internal structures of the hair—the cortex and the medulla—from physical and chemical damage,” de Pons explains. “If we look at the cuticle under a microscope, we will see that it is made up of a set of flat cells that, due to their arrangement, are very reminiscent of the tiles on a roof.”
This visual analogy is helpful when thinking about how pH affects our hair. “The pH of the environment we are in can completely modify the structure of our hair. If we place ourselves in a pH gradient from acidic to alkaline, we will see that in a completely alkaline pH—the opposite of acidic—the cuticle of the hair is completely open,” de Pons says. “With an alkaline shampoo, the ‘shingles’ of the cuticle become completely perpendicular, looking more like the branches of a fir tree projecting from the trunk.”
The effect of pH is super obvious when hair is bleached or subjected to permanent hair color treatments: “Ammonia, which is alkaline or basic, opens the cuticle to allow bleach or dye to penetrate the hair cortex. The application of shampoos, conditioners, masks and other treatments—which are generally acidic—allows those “shingles” of the cuticle to contract,” de Pons says. “When the tiles are stacked alongside each other so much so that they become almost imperceptible, which makes our hair shine. In the end, it’s the smoothness of the cuticle that reflects light.”
Your new ritual for shampooing
“When a formulator creates a shampoo, he thinks about the correct application of the product. As a user, it’s important to use that formula as it’s intended; as it has been designed to be used,” de Pons explains, adding that most shampoos are actually formulated to clean the scalp and therefore should be applied to the scalp and nothing else. “Advertising has done a lot of damage in this sense; we tend to imitate the fancy gestures seen on television commercials. We scrub and scramble our hair, which is completely incorrect,” reveals de Pons.