Do You Really Need Shampoo?

A new, suds-free approach to washing, called “co-washing,” might just eliminate shampoo—and put an end to your bad hair days.

Photo by Jamie Chung

Co-washing is short for “conditioner-only washing.” It means skipping shampoo and relying solely on conditioner, whether you’re a daily or a weekly washer. The result is something between squeaky-clean and second-day hair—that is, smoother, softer, and easier to manage. A fringe benefit? You’ll save shower space, as well as some time and money.

Are You a Candidate for Co-Washing?

If your hair is dry or it’s curly or wavy (both of which tend to be naturally dry), chances are that you’ll benefit from co-washing. In fact, legions of ringleted women have been washing with conditioner alone for years. Why? Most conditioners contain trace amounts of detergents called cationic surfactants, or “quats” for short. (Some common types that you can find on your conditioner’s ingredient list are cetrimonium and behentrimonium chloride.) When mixed with water, the quats pick up tiny amounts of dirt, leaving unshampooed hair feeling clean but not squeakily so. At the same time, the conditioner contains, well, conditioners. “Since unshampooed hair retains more of its natural oils than shampooed hair, the conditioner’s moisturizing agents will now leave strands even smoother and silkier than usual,” says Nicole Tresch, a senior colorist at the Rita Hazan Salon, in New York City. Assuming that they have healthy scalps, women with color-processed hair are also prime candidates for co-washing, as it allows them to go longer between salon treatments. “Co-washing doesn’t strip strands of pigment the way traditional cleansing can,” says Los Angeles hairstylist Jen Atkin. Whom isn’t co-washing good for? People with fine, straight hair, which could get weighed down. Those with an oily scalp or dermatitis should steer clear, too. “Co-washing alone doesn’t effectively treat either condition,” says Jeannette Graf, a New York City dermatologist. Stick with your regular shampoo-then-condition routine.