How long will it take for this hair product to work?

i bought the john frieda brilliant brunette shampoo, its supposed to make your hair a shade darker..but it doesnt say how long it will take to be noticable. anybody know?How long will it take for this hair product to work?
A lot of products take between 2-4 weeks to become noticeable. However, I used the same shampoo and didn't notice any changes I hope it works for you, though. Good luck.How long will it take for this hair product to work?
I have the john frieda for blonde, but I have only used the highlighting one. It has worked for me between drying time and the next day. I think it may take longer for the product you have because all mine had to do was bring out my highlights; not create any.
I got that too and noticed results in about of week of using it, however I noticed it messed up my hair colour. The colour didnt take everywhere and it made my roots lighter....i'd be careful



that stuff sucks