I actually used this product two different ways.

At first, I had virgin hair so I just used it on top of my medium brunette colour. It came out a nice burgundy shade and lasted me a few weeks. Then, I added some blonde streaks and put this colour over the streaks. It lasted me a little longer because bleached hair is more porous. After doing the streaks my hair was super dry, however MP products are moisturizing. I kept the colour in for a few hours since it's non damaging, and when I washed it out and blow dried my hair, my hair was ridiculously smoothed.