Use of heat is necessary for results
As ONC products do not contain chemicals to open the cuticles. After the color mix is on the hair. Use the ONC Thermal Heat Cap, or medium heat from a hair dryer. This opens the cuticles so the color can go into the hair. Only use heat on the roots or regrowth hair. The ONC Thermal Heat Cap is healthiest. As it opens the cuticles using trapped heat from the head. It also prevents overheating, which dries hair out. Don't forget - USE HEAT!