Hair Purifying Shampoo is designed for extremely swift yet elegant removal of all toxin residues. Within 10 minutes, you will be in the "Clean Zone" for up to 4 hours. It is safe for the scalp and all hair types. It does not effect color or specific gravity. Works as a "body wash" for body hair in addition to scalp. Drug testing via hair follicle sample has grown into a very popular method to detect drug use without invading ones so-called privacy compared to a urinalysis or a blood test.