Olaplex No.0 Intensive Bond Building Treatment is a professional-inspired hair treatment designed to prime, repair, strengthen and protect all hair types. This innovative formula features the highest concentration of Olaplex's patented bond-building technology for at-home use. Key features: • Professional-grade bond building formula • Primes hair for enhanced treatment results • Repairs and strengthens damaged hair • Protects all hair types • Contains highest concentration of Olaplex technology for home use • 155ml/5.2 fl oz spray bottle format For best results, apply to dry hair and saturate evenly from roots to ends. Hair should be damp but not soaked. Leave on for 10 minutes before applying Olaplex No.3 Hair Perfector (sold separately). The treatment works by finding single sulfur hydrogen bonds and cross-linking them back together to repair and strengthen the hair structure from within. This is the first step in the at-home Olaplex bond building system.