This type of hair color product containing peroxide and ammonia. Can make hair darker or a few shades lighter. Permanent hair color treatment lasts until new hair grows out. Like Demi-Permanent, roots need to be touched up every 4 to 6 weeks. Cover gray completely. Disadvantage of permanent hair color is growth of new hair. It is a different shade and will leave a line. Permanent hair colors can also dry out your hair and cause damage, unless you use good moisturizing products.
Permanent hair color will remove your previous hair color pigments and deposit new pigments deep into hair shaft in one step. Process is harsh and damaging to hair and must be handled with care, so if this is your first time coloring your hair then stay away from this type of coloring or go to a salon professional. Salon professionals can regulate amount of peroxide (10%, 12% or 20% developers) to acheive optimum resulting shade with less damage possible.