formaldehyde not safe stars [SEP] after going over the ingredients in these products the only two i would feel even remotely safe using would be this shampoo and conditioner as a hair stylist you do not want to use a product that contains formaldehyde and apply heat to it you certainly do not want to use it every weeks as it is harmful to your health it can cause breathing issues among other things it is very hard to believe that i even saw actual formaldehyde on the back of this product and so high up in the ingredients listeven hair stylist must wear protective gear such as gloves aprons masks and be trained how to safely work with this hazardous chemical salons must have adequate ventilation and follow strict protocols regarding blow dryer temperatures and monitor formaldehyde levels at all times when they provide keratin treatments containing formaldehyde because of the immediate and long term health dangersthis is something you cannot possibly do at homealso the pretreatment that you add to the shampoo is extremely strong and stripping to your hair when they say add just a little no one knows what that means that particular product or the two main ingredients should only be a small percentage of the product you are adding it to i do not think you can mix this properly at home without causing damage to your hair and or your skini might use the shampoo and conditioner but i will not touch the pre treatment nor will i touch the diy home keratin treatment over the course of a few treatments i can see this product going really awry for some people they will end up with damaged hair and possibly other problems it is not safe i absolutely would not recommend it