Are you co-washing your hair?

Shampoo is out, conditioner is in.

Many salons and stylists are recommending a pared-down hair care routine to clients: A conditioner-only regimen, otherwise known as co-washing.

The theory behind co-washing is this: Since conditioner has no sulfates, no detergents, and is not oil-based, it doesn’t interfere with the natural chemistry of the hair (whereas shampoo can strip natural oils and dry out hair). Conditioner adds nourishment and hydration to each strand, and still cleans the majority of buildup that shampoo would otherwise eliminate. For athletes and gym-goers, who tend to take more showers, co-washing can spare hair from over-shampooing.

“A lot of people have to deal with their hair getting puffy and dry when they shampoo,” says Jeff Chastain, stylist and founder of the product line PARLOR by Jeff Chastain. “Using only conditioner can still gently clean the hair, if you really scrub it everywhere, and right into the scalp. The moisturizing that comes from conditioner gives hair some weight to keep it under control.”

Shampooing isn’t entirely bad, though, so an infrequent shampoo—in addition to a daily co-washing routine—is a better way to go.

“The scalp does need a good sudsy scrub,” Chastain says. “And styling products can build up overtime. I recommend that women shampoo when they feel like they are getting too greasy—this varies from one person to the next, but you be your own judge," he says. Chastain also adds that men should add in shampoo every week or two, at the very least; some will get greasier much faster, even if they scrub with conditioner. "Some people’s scalps need more attention with scrubbing or they can get dandruff or itchy spots," he says. "Use shampoo when you feel like your scalp is getting to that point or when there is too much residual product in your hair to style it properly.”

Chastain suggests using a conditioner that's focused on volume and texture. It won't build up nearly as quickly as a traditional conditioner that's meant only to tame hair.

Co-washing is especially helpful for maintaining natural waves and curls. People with this kind of hair should condition every day to prolong the natural texture, and avoid blow-drying. However, if your hair is straight or if you recently got it blown out, you will probably need to shampoo sooner, since your 'do will start to feel heavy much earlier on.

Newbies joining the conditioner-only game might realize how impossible it is to build conditioner into a lather (since it has no sulfates); this presents a challenge for distributing it evenly. Chastain recommends starting at the back of the crown—only when the hair is very wet—and working out from there. Again, be sure to scrub thoroughly.

“You won't get a lather,” he says. “But you will feel clean when you finish.”

And, if you’re going to try a no-shampoo (or infrequent shampoo) approach, Chastain suggests adding the following products to your styling and maintenance routine:

Dry shampoo:“Use it in moderation, to soak up some visible oils.”

Light styling and curl creams: “They can help define a look without adding any oils or increasing buildup.”

Texturizing and sea salt sprays: “They’ll each give you a great tousled look with a natural finish.”