I liked this product but won't purchase again. I think if did definitely help with the brassiness on my ends, but only after the third time trying to use it. first time I left it in for 10 minutes and noticed no difference, the second time I left it in for 20 minutes and maybe noticed a small difference in my blonde ends. The third time I left it in for about 40 mins and I noticed a big difference. All the brassy colour was gone and I got lots of compliments the next day. I have pretty thick robust hair that takes colour really well and isn't prone to damage so that could have been a factor in why it didn't work following the instructions for me.