"I purchase this product and read the instructions carefully. I even watched several YouTube videos to be sure. I conducted the 48 hour test patch, which showed no adverse reactions. However, after using this product my skin started burning while it was only on my face for a few minutes. I washed if off with the recommended shampoo right away. Unfortunately, my skin was burring and itching something horrible. Even days after the skin under and around my mustache are still irritated. I don't have sensitive skin so I'm positive it is the chemicals in this product. Knowing what I know now, I should have just lived with the grey hair in my mustache."