Yes, when you touch it up, some of the previously highlighted hair is getting bleached again!! That's why it's so damaging. The first time I got my hair highlighted, it was fine. After the second time (about 9 months later)I started getting a whole lot of breakage, especially in the front. It was awful; I would NEVER get my hair highlighted again. Keep in mind though, that I also had my entire head dyed previous to the highlights. For someone who just gets highlights on top of their natural haircolor, maybe it wouldn't be as damaging.