People who relax their hair know some coloring processes can be damaging to processed hair.
That’s why it’s natural to worry about over processing when you apply a relaxer to previously relaxed hair.
Nevertheless, a keratin treatment is good for colored, highlighted, or previously processed hair. If you use a non-acidic relaxer, the procedure will provide you with favorable results. It can also be a good variant if you are eager to transition from relaxed to natural hair, giving some time until the relaxers grow out.
If you want a new hair color, it's advisable to dye your hair 2 weeks before or after the keratin treatment. However, some hairdressers can do it the same day.
In any case, it’s better to consult a stylist first. You should tell him/her everything about your hair and all the processes that it has undergone before. After this, the hairdresser will make a decision what to do and what products to choose.