Highlights can be very tricky. When hair is highlighted, usually bleach is involved. This can make the timing judgement very difficult because some hairs are lightened right next to hair that is not lightened. Therefore the hair may process faster where highlights are present and need much more time where the hair is dark and unprocessed. In order not to over process the light hair, the solution should be to rinse out and the darker, healthier hair may not take. A prior consultation with your stylist is strongly recommended to determine whether Japanese Hair Straightening will be a applicable for those with highlighted hair.