OLAPLEX No. 0 Intensive Bond Building Hair Treatment is a professional-inspired, intensive treatment that primes hair for deeper repair, strengthens, and protects hair integrity leveraging the OLAPLEX patented bond-building technology. It primes hair to intensify benefits of the No. 3 Hair Perfector, strengthens weakened bonds deep within the hair strand, and repairs hair from chemical, thermal, mechanical, and environmental damage. Scientifically proven 3x stronger & 68% more repair when used with No. 3 Bond Perfector. Vegan & cruelty-free. Suitable for all hair types.