Thank you for your question. Please follow all directions that come with the home haircolor kit. This includes you doing an allergy patch test AND a stand test before applying any new color formulation to your entire head. Ecocolors medium brown will be a light brown on gray hair. It might encourage red tones in your other hair. If you do not want red tones, use the medium ash brown. After doing the strand test, and the color is satisfactory,use the plastic cap that comes in the kit when ou do the real haircolor application and leave the color on the gray hair for at least 35-45 minutes for fiull coveage.
