Shampoo Could Be to Blame For Your Frizzy Hair

Updated on 2/19/2015 at 8:00 AM

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Frizzy hair is frustrating — especially when the cause is unknown. Allure reveals the culprit hiding in your beauty routine (and we're not talking about sulfates).

A new study found that the pH level of shampoo has a direct effect on how frizzy and prone to breakage your hair is. Basically, that means that loading up on hair masks and smoothing serums still isn't enough if you want to get seriously sleek, frizz-free hair. Kristin Sainani explains the science behind the finding.

Frizzy, unruly hair may be caused by shampoo with a high pH. (Quick chemistry review: pH measures acidity; a pH below 7 is acidic, a pH above 7 is alkaline, and 7 is neutral.)

Shampoos with a pH above 5.5, the pH of the scalp, can cause a buildup of static electricity that leads to flyaway hair, friction, and breakage, according to researchers in Brazil. These effects can occur in all hair types, but hair that is coarse, curly, or chemically damaged from dyeing or straightening has less lubrication and a thinner cuticle layer, making it especially vulnerable, says lead study author Maria Fernanda Gavazzoni, a professor of dermatology at Federal Fluminense University in Rio de Janiero.

Of 123 products sold in Brazil that she and her colleagues tested, only 38 percent had a sufficiently low pH. Professional brands (found in hair salons) were more likely to be formulated correctly. Gavazzoni advises women to look for shampoos labeled "pH balanced" or "low pH" (conditioners usually have a low pH, she adds) and to avoid overusing clarifying shampoos, which employ alkaline ingredients to enhance cleansing by opening the hair shaft.