Is dry shampoo bad for your hair? I guess the answer is that it depends on the ingredients.
The problem with dry shampoo is that you spray it directly on to the roots of the hair and rub it in to the scalp, this is of particular concern if the chemicals in the dry shampoo are left on the scalp for several days.
In leaving theses chemicals on the scalp for several days you are increasing the risk of the skins pores becoming blocked and more worryingly the chemicals being absorbed in to the skin.
If the pores on the scalp and the hair follicles become clogged with dry shampoo this could inhibit hair growth this could be of particular concern for anyone suffering from alopecia.
Many of the chemicals in dry shampoo have the potential to aggravate dermatitis eczema and other such conditions.
If you feel the need to use dry shampoo then I would recommend using a product made from more natural and gentle ingredients, one such product that has recently become available is Revive made by organic colour systems. Revive is based on organic and natural ingredients making it less toxic and kinder to the skin, its also much lighter in texture and so less likely to clog the pores and follicles.