There are cleaning agents in co-wash, just not the bubbling ones you're used to. "Many conditioners contain trace amounts of detergents (surfactants), which cleanse the hair shaft of dirt and leave the hair clean but moisturised," Dr. Ingleton explained. But no matter what, conditioner won't get your scalp as clean as classic shampoo will. Think of co-washing as more of a refreshing process. "If my clients are heavy gym-goers, this is a perfect daily routine," said Willhite. "It allows the user to work up a sweat without worrying about fragile hair drying out." To use, massage the co-wash into the scalp and roots, work it down to the ends, and rinse thoroughly.