Most of the keratin complex solutions on the market today, including Coppola Keratin Treatment, have shampoo and conditioners that were created to help maintain the keratin and make it last longer. It’s up to you if you want to use these products.
If you have your keratin treatment done in the salon, they will typically use the keratin shampoo to cleanse your hair before the treatment. Since you must least the keratin on, 72 hours for the full keratin and 8 hours for the keratin express, it will be up to you do wash your hair after the keratin has taken effect.
The biggest reason to use the keratin shampoos is that they don’t contain any ingredients that will strip the keratin out of your hair faster, like sulfates. If you choose to use a different shampoo or conditioner you will have to read the ingredients to make sure there are no agents that will strip your hair. I personally use my own conditioner and I don’t shampoo at all (I’ve followed the Curly Girl routine by Lorraine Massey for over a decade) and my keratin has lasted the full 6 weeks as expected with the express treatment.