Simple Tree's Indigo is 100% pure. You can use it solo to darken existing dark hair, to make brown hair deep black and to darken any of our henna hair dye colors. Most often it is used in the 2 step process to colour your hair black naturally. In the first step you have to apply henna on your hair and the wash it off, and in the second step you have to apply Indigo, to get that dark brown to black colour hair shade. Detail instruction are given in the instruction leaflet that comes with this pack.