I used the metallic blonde colour booster in silver, and it made my dark blonde hair a rather barbie shade of yellow! Not at all what I was hoping for .. :'( But i saved it with Goldwell 10P toner. I wouldnt buy it again, it looked nothing like the picture on the box. Next time I want to dye my hair, I'm going to the hairdressers!
I have black hair and decided to go for Colour Booster since it seems to be able to show on darker hair colours. I went for a light brown colour and proceeded to use it. It didnt show the first 30 minutes as specified as my hair was black, so I let it sit longer and after 2 hours or so I can begin to see a lighter tinge in my hair. I washed it out after 4 hours or so and it left an orange-y copper colour. After a few weeks my hair got considerably lighter and is now a copper colour.
I would recommend this product to the darker hair people who wants a DIY hair colour that works, but on't expect it to be the colour as seen on the packaging.
This is a variation of their popular Feria hair color, but has an added "Color Booster" which is supposed to give super vibrant colors. I bought this in Pure Power Spice, which is a bright, intense red. I like this better than Feria mainly because the colour shows on me. I have coarse black hair which resists colour like crazy and this one at least shows up in a slightly red tinge on me (it will never be that terrific color on the box!!) A shampoo is included which is supposed to get rid of stains on your scalp and that's great (I had horrific stains from Wella's Red series, got everywhere except on my hair). Only thing I don't like is they don't include a conditioner, which is rare for hair colours. I had to use my own conditioner as after the shampooing, my hair felt as dry as grass. But my regular conditioner works fine, so no complaints :)