DescriptionA professional-inspired treatment that prepares hair for deeper repair with the highest dose of OLAPLEX technology patented in any take-home product. Rebuilds hair joints, strengthens and protects hair integrity. Use it as a first step in a two-part system with No. 3 Hair Perfector. Scientifically proven: 68% more repair and hair 3 times stronger * * When used as a two-part system in single use.MODE OF USEBottle No. 0 should last from 3 to 6 applications, depending on the length and density of the hair.