A professional-inspired treatment that primes hair for deeper repair with the highest dose of patented OLAPLEX technology in any take-home product. What It Does • Primes hair to absorb nourishment for maximum repair • It rebuilds hair bonds, strengthens and protects hair integrity What Else You Need To Know • Use as the first step in a two-part at-home system with No.3 Hair Perfector (sold separately) to strengthen and repair all types of damaged hair •Scientifically proven: 68% more repair & 3x more strength *When No.O & No.3 are used as a two-part system