I bought this because I'm trying to grow in my natural color, an ashy light brown that contrasted with my old highlights - now a brassy-gold. I mixed this with developer and applied. For the most part, it cooled my hair color way down. I had a few very pale highlights that this turned violet. The only thing I really didn't care for (besides the smell) was that it did dry out my hair a bit. It wasn't any kind of severe damage but I did baby my hair after using this. I will definitely turn to this again instead of trying to color my old highlights ash brown. It looks more natural.
I have medium brown hair that I dye at home (formerly highlighted blonde) and dislike how my color fades into a coppery shade that I don't care for. I don't want to keep coloring my hair dark in order to keep this undertone at bay so I picked up the violet intensifier and used it only with developer. My color had depth and I recieved compliments (hence the name). I noticed the color washing out in my towel for around a week and after around two weeks the color was almost gone. I would classify this as more of a semi than a demi since it washed away so quickly. Maybe if it was used along with regular dye and not just developer the results would last longer. Tt's fun to play around with but use caution if you have light hair