A damning Healthline report argues that because dry shampoo doesn’t actually clean your hair, but instead absorbs oils, it can dry out your scalp considerably. Likewise, dry shampoo is an aerosol-based product, most often containing alcohols, which can dry your hair out. When it’s dry, your hair is more prone to breakage, as individual fibers can crack or snag on each other when you brush or style it.
Using dry shampoo too frequently, or leaving it in your hair for too long without washing it out, leads to a buildup of product on your scalp, which makes it itchy and can even lead to folliculitis, a bacterial or fungal infection in the hair follicles. Although dry shampoo hasn’t been found to cause dandruff, it does make oils cling to your scalp which, as a study by the Mayo Clinic found, can lead to the flaky condition.
There’s nothing concrete to suggest dry shampoo causes hair loss, but poor scalp health can and, if excessive usage leads to damaged follicles or even a bacterial infection, new hair growing from the follicle is more likely to break or fall out.