A weekly at-home treatment, not a conditioner, that reduces breakage and visibly strengthens hair, improving its look and feel. PRO TIP: Prime your hair for deeper repair with our professional-inspired No.0 Intensive Bond Building Hair Treatment (sold separately). Use No.0 as the first step in a two-part at-home system with No.3 Hair Perfector to strengthen and repair all types of damaged hair. Scientifically Proven: 68% more repair & 3x stronger hair* *When used as a two-part system in just one use.