However, when it comes to scalp health—and more specifically, the use of dry shampoo—the line between safely extending a blowout and potentially causing scalp inflammation is a very thin one. “You can do long-term damage to your scalp by washing infrequently and using dry shampoo often,” explains expert trichologist and hairstylist Shab Reslan. “Healthy hair starts with a healthy scalp, and dry shampoo is not your friend in that quest.” “You need to remember that dry shampoo does not truly cleanse the hair, it is only absorbing the excess oils from the hair and scalp,” explains Vickie Vidov, a hairstylist in New York City. “If not properly cleansed and removed from the scalp, a film residue will eventually build up, resulting in clogged pores.” Attempting to mask dirt, oil, and pollution with a dry shampoo only adds more grime to your scalp and hair. Like attracts like, so the buildup you’re adding to your scalp by using dry shampoo has a sort of snowball effect. Over time, this exacerbates another already problematic quality of dry shampoo: It’s really difficult to truly slough off.