Lather, Rinse, Repeat? Our Hair Experts Weigh In On The 'Shampoo Twice' Trick

Perhaps the seasoned phrase "Lather, rinse, repeat " conjures up black and white images of shampoo commercials with ladies sudsing up beyond necessary. But the actual meaning itself, when you think about it, feels archaic. When you washed your hair this morning, did you rinse it out and repeat? Probably not. Though some bottles have clung to these instructions, is it still necessary to wash your hair two times in a row ? Was it ever? We decided to call in the experts.

In this week's installment of Beauty Myths, we tracked down hairstylist Philip B , founder of the eponymous haircare line, along with Sandra Gilman, trichologist and educational director for The Elan Center for Trichology , to clear up this lingering hair theory, and whether it's bad to heed this seemingly dated advice.

"Not necessarily," Philip B says of washing hair twice. "If you're not a frequent shampooer, two vigorous shampoos can help remove a week's worth of residue, pollution and product build-up. Likewise, if you have a troubled scalp, shampooing twice is a good idea: Start with a clarifying shampoo to remove part of the barrier coating on the scalp (i.e., clear away the dead cells and waxy oil), and then go back in with a medicated shampoo. That will help the healing ingredients penetrate and do their work. Either way, your scalp should have a clean and fresh feeling when you get out of the shower, the same way your face feels after you wash it." Gilman agrees that cleansing hair two times in a row is acceptable for someone who uses a lot of products and gels, as well as those who work in an environment where they are exposed to lots of dirt or pollution. She notes that "the problem, however, is excessive shampooing can remove too much of the natural oils (sebum) from the hair which is necessary to maintain the hair in its comfortable acid/base environment (pH)."

If "lather, rinse, repeat" seems to apply to those using heavy products, overly oily scalps or exposed to lots of pollution, where did this thinking come from? Especially the suggestion to do it on a daily basis. "The shampoo-twice thinking probably came from manufacturers who wanted to sell more shampoo ," says Philip B. "Then again, back when they first started marketing shampoos, most people werent daily bathers, much less daily shampooers. So recommending two shampoos meant simply promoting good hygiene. And it was easier, too: Rather than list a lot of instructions, the manufacturers just suggested a blanket, two-times wash."

So how different is this squeaky-clean approach from a clarifying shampoo? (Which we'd always been informed to use sparingly, no more than once a week, spaced out even more depending on your hair type.) "A clarifying shampoo is usually clear, without many buffers or oils, and designed to deep clean your hair and scalp. A rich, creamy, moisturizing shampoo offers less intense cleansing -- using it twice would be like applying moisturizer twice."

Ultimately, it's about finding the right balance for your hair, says Gilman. "People with curly or excessively curly hair have learned by experience that a little build-up sometimes makes the hair easier to manage, and waiting a few days between shampoos makes a world of difference. On the other hand, those with fine hair may get greater manageability by shampooing frequently."

Conclusion: Depending on how much pollution, oil, dirt and styling products the hair is exposed to, as well as how often it's being washed, two shampoos can be effective. However, it should never reach the point of "excessive," which will deplete the hair and scalp of healthy, natural oils.

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