Who shouldn't use it: Japanese hair straightening cannot be performed on fragile, relaxed or henna-dyed hair. It is not recommended for people of African descent. If Japanese hair straightening is performed on unsuitable hair, or if it is performed by an inexperienced or careless stylist, it can cause hair to break off. This risk is especially high with touch-ups.
Other side effects include burning of the scalp and nausea. â€œVirginâ€ hair that has never been dyed or chemically treated can be more resistant to the process, leaving wavy pieces. Make sure to ask what your salonâ€™s re-do policy is, as some stylists may charge more to fix resistant locks post-straightening.