I have a white skunk stripe that appeared after a major surgery, I assume it’s a result of stress. I didn’t expect this product to work on it as it’s pure white. What I find is that if I use the anti-grey restoring treatment every morning, it blends well with my dyed hair and hides the grey between colorings. In my case, it does wash out, there has been no restoration of natural colour. But I find that the benefit of never showing grey roots is well worth the price, this works better than any other product I’ve tried. I do recommend wearing gloves to apply, because it will tint fingernails. (Remember - fingernails are keratin too, just like hair) There is a slight smell when the product is wet, but goes away once dry. I like that it is completely unnoticeable, no mismatched colour, doesn’t make my hair stiff, and if I apply daily it can survive one washing without fully disappearing.