Works best on bleached hair as it has a brighter colour and fades less. I used it on half bleached/half not bleached and it worked really well. Needed about 3 bottles due to the length of my hair but was happy with the results. It did fade but to a nice light blue on bleach and a dark shine on non bleach. Very happy with the result though regular reapplication is needed if you want to maintain the colour. -Gem-