Actually except for the few grays I have which are now copper my hair color hasn't changed enough to be noticed. The first time I did henna I waited all day for someone to notice and no one ever did then or since. My hair is natully reddish brown and it still is. Also the color depends on what kind you use. You might also try Cassia aka Neutral Henna.
Low porosity, high density, and fine
4a/3c, mod-CG, itchy prone scalp
Natural 4 Life