This really depends on the condition and the porosity of the bleached hair. Ecocolors may be used as a toner by diluting the entire color mixture by half with water before applying to the hair. You should always do a strand test and a patch test before application to your entire head. Bleaching the hair causes lightening at least 4 levels and weakens the integrity of the hair shaft. Overall I would say anytime you have bleached hair and you apply another chemical you are doing so at your own risk.(including Ecocolors Haircolor)
