I've tried Perfect 10 for the past 3 months. My hair is very strong and takes quite a bit of abuse. In the past I've used chemical straighteners to tame my natural waves, all the while coloring over gray and using a blow dryer and flat iron. But in the past three months since I've started using Perfect 10, I have seen a noticible amount of breakage in my hair. I think I'm going to have to use some heavy duty conditioners, minimize the flat iron, and switch back to L'oreal.