Not sure why many people are saying that this products doesn't work on hard to cover grey hair. I'm in my 50's and I've been using this product for more than 10 years and have very grey roots. I mix two colours. 8N and 10N and only re do roots every few weeks, which takes about 20 minutes to apply. Leave it on for 40-50mins. The best coverage and best naturalish alternative to harsh dyes. Also astonishes hairdressers when I get my hair cut, because they all say the colour is awesome and very natural as well as keeping the hair in great condition, all things you dont get with harsh hair colours. I'm so pleased with this product I buy 12 at a time and take it overseas with me when I travel etc. Anyway...I can only say great things about this product and would be lost with out it....Thanks, Tints of Nature for keeping on doing your thing!