This product supposedly does not contain formaldehyde and adds collagen to the formula in addition to the keratin. It may contain a derivative of formaldehyde, but I am not certain. It is my understanding that all keratin treatments have some form of formaldehyde in varying degrees. I did notice a brief smell that irritated my nose similar to nail polish remover for a few seconds. My stylist did not wear gloves or a mask, as I have read from other folks online. She did have a fan on for the blow drying, however. My hair took to the treatment very well. The most noticeable difference was after the waiting period when I washed out the treatment. My hair did appear to retain it's natural curl pattern, but it was a bit looser and much easier to comb and style. Ironically, as my hair air dried, the curl stretched out more instead of drawing up and tightening more. My hair is still very soft and shiny and easy to maintain in this awkward transition state as I grow out my relaxer. My hair is not at all frizzy or puffy at the root where I have my new growth. I work out and sweat and it does not ruin my hair. I go out in high humidity and heat and it is still smooth.
I do believe there is a lot of fear and ignorance being spread about the treatment. But the truth is that the primary chemical in a relaxer will melt a hole in your head if you leave it on too long. No one is spreading fear about relaxers burning women's scalps on a daily basis across the world. In my opinion this treatment eliminates the need for anyone to ever get a relaxer unless they really don't ever want their natural curly hair. I definitely feel that this is a viable option for those of us that want our natural curly hair with the added option to wear it silky straight without a ton of effort/heat, that won't puff, revert or frizz in hours.