Ouai Dry Shampoo Foam "If there's one product you should always keep in your gym bag, it's Ouai's Dry Shampoo Foam ($28). Unlike regular dry shampoo sprays, this comes in the form of a mousse that quickly freshens greasy hair. It's saved me countless times in between washes and after workouts when I just don't have time for a full shower." — NY Ouai's Dry Shampoo Foam $28 from sephora.com Buy Now