I have a patch of psoriasis right in my sideburn area. I have highlighted curly hair that tends to be dry and frizzy. Consequently I am nervous to use this product on my whole head. I shampoo my hair with my usual product, rinse out then put my conditioner in, I rub a little bit of Polytar in to the spot of psoriasis then leave it in while I soap up, shave and rinse. Then I rinse the Polytar and conditioner out of my hair. This gives the product time to work and keep the psoriasis to that small spot.