What It Is:A professional-inspired treatment that primes your hair for deeper repair, rebuilds hair bonds, strengthens and protects hair integrity.What It Does:Redesigned for a quick and targeted stream application, the No.0 Intensive Bond Building Hair Treatment features an easy to use nozzle that primes the hair and delivers the highest concentration of the patented bond-building technology of any Olaplex at home product. Primes hair to intensify benefits of No.3. Jump starts repair deep within the hair strand.How To Use It:- 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.- Apply slowly to dry hair, distributing evenly from root to tip. Work No.0 into small sections by squeezing the liquid into the hair to be fully absorbed as you go. Hair should be damp, not drenched. Let process for 10 minutes. Do not rinse. For the complete treatment, apply No.3 Hair Perfector over hair with No.0 applied to it, combing through as needed. Let process for a minimum of 10 minutes. Rinse, shampoo and condition. For best results, use No.4 Shampoo and No.5 Conditioner.- Brush or detangle hair before applying No.0 so it can easily be absorbed. For thick, coarse or long hair, work in small sections to ensure each area is fully saturated.- No.0 bottle should last 3-6 applications, based on hair length and density.About The Brand:Olaplex products are thoroughly tested in accordance with industry standards in-house and by independent third-party laboratories for safety and efficacy.