NO.0 powered by patented olaplex bond building technology, our professional – inspired treatment primes hair for deeper repair & strengthens hair bonds while protecting hair integrity boosts the efficacy of olaplex NO.3 hair perfector, strengthens & rebuilds hair bonds, absorb quickly to jump- start repair deep within the hair strand. How to use: – Apply to dry hair, fully saturate from root to end. – Leave on for 10 minutes, do not rinse. – Put olaplex NO.3 hair perfector for 10 minutes. – rise with shampoo NO.4 & conditioner NO.5.