I had no idea how much grey hair I had until this brought my hair back to life. Similar to other reviews, my whitest/greyest hairs came out looking like highlights. What I didn’t realize, was how much of my other hair was starting to gray, so I ended up with more color than I expected. It also seems to be strengthening my hair — the top of my hair strands are visibly thicker than the bottoms. Couple tips- definitely get 2 bottles, even if you only need one for the first month, it’s nice to have the second one for ongoing treatments. Also, I didn’t love the packaging, so I transferred it into an empty hair developer bottle with a long skinny tip, and added a bit of water. This made it much easier to apply, both for spot treatments, and all of the back of my head. Had less stains on my hands this way, as I didn’t need to use my hands as much. The water also helped it not make my hair quite so stiff (which wasn’t bad, kind of like having a bunch of mousse in your hair).