Hair colour changes and quickly fades day after day, no matter which brand is used.
This means we see a colour that turns lighter or loses its intensity very quickly, and a blond that looks yellowish just a few hours after the colouring or bleaching application.
This happens because the reaction between the hydrogen peroxide (inside the developer) and the amines (inside the colour cream) or persulfate (inside the bleach) is a chain reaction, so once it has started, it will finish only when every molecule of oxygen has been consumed.
It’s very hard to stop the oxidation process because the oxygen present in the air and in the water pushes the oxidation non stop!
Using a traditional post-colour shampoo and/or mask after the colouring treatment doesn’t solve the problem even if the pH is very acidic.
These kind of treatments in fact just close the cuticles, but they are not designed to extinguish all the remaining oxygen molecules inside the hair shafts.
For this reason, the oxidation process never stops.
After colouring and bleaching, there is an understimated crucial need to: