it works on grey hair
I have been using this dye for years with no reaction. On my grey hairs it is always a lighter brown than the rest of my dyed hair. I have tried using a shampoo to remove all product and oil buildup prior, and leaving the dye on the grey areas longer, but still comes out a lighter brown. In order to achieve the dark brown on the box I need to dye the grey area twice - ie another dye of the light brown the following day.