Overtone Extreme Blue has been a Life-saver for my blue balayage highlighted hair! It's been over 7 months since my last professional dye and I still have vibrant color thanks to this deep treatment and the conditioner. I have very dry ends so this deep conditioner nourishes while it colors. It also smells great!
As stated in the directions, you'll get the best and brightest results when used on dry hair and left on for 15 minutes. When I've been in a rush I've conditioned in the shower for about 10 minutes and I still get a good glow, just not nearly as bright so you might as well stick to the conditioner in the shower and the deep treatment 1-2 times a week, if you can spare. It leaves my hair refreshed and I'm going to keep putting off that next dye for as long as possible!