I purchased the 3 step system on the advice of my hair stylist - she was a strong advocate for the product and I'm really bad at saying no :) Needless to say my hair was getting a bit thinner than I'd like especially at the top (due to breakage more than anything) so I was open to trying something new before I developed a bald spot. Used the products for approximately a month and I guess there was a reduction in the breakage but my hair felt really dry and coarse which I wasn't too pleased about. And then the trouble started. I noticed a bit of a dry spot on my forehead which progressed into a rash. I was breaking out in fine, itchy spots along my cheeks as well. According to my doc it was allergic contact dermatitis and was particularly bad on my forehead because of my fringe. She recommended I stop using the Redken products and it cleared right up afterwards. These days I try to stay clear of products containing methylisothiazolinone (MI) or chloromethylisothiazolinone which trigger the reaction I got from the Redken system. As an added precaution I prefer to use sulfate-free shampoos if possible. So if you have sensitive skin or suffer from dermatitis perhaps not the products for you.