Well the great news is your permanent hair color is awesome and my stubborn white hair gets completely covered with your hair color. It covers wonderfully and my hair looks super shiny and looks great. Now the henna cream I was very disappointed in because it did not cover the white at all and it looked as if I did nothing to my hair. I did use light brown and my natural hair is medium brown because of the permanent color having a tendency to go darker, I was trying lighter and that might have been what caused it to not cover. So improvement on the henna cream to cover white/gray hair would be great. Overall I love your permanent color and would highly recommend it.