Henna is actually the only hair dye that doesn't damage hair and can even serve as a reinforcement treatment. However, this natural product doesn't contain harsh chemicals that open your hair cuticle and penetrate the color deep into your hair, so the color is not permanent. It will fade during the course of 1-2 months so you need to renew the color regularly (the good thing is that you don't have the white root problem as much) The most important thing to keep in mind for a successful regular henna coloring is to avoid doing it too often. Henna buildup can be pretty nasty so you should be careful not to do more than 1 treatment a month or even every second month, depending if the color is still fine enough.