Water (Aqua), Bis-Aminopropyl Diglycol Dimaleate, Sodium Benzoate, PhenoxyethanolA professional-inspired treatment which primes the hair for a deeper repair, rebuilds hair bonds, strengthens, and protects hair integrity. Use as the first step in a two-part at-home system with N°.3 Hair Perfector to strengthen and repair all types of damaged hair. Scientifically proven: 68% more repair & 3x stronger hair* How to use: 1. Apply N°.0 slowly to dry hair, distributing evenly from root to tip. 2. Work into small sections by squeezing the liquid into the hair to be fully absorbed as you go. Lightly saturate. Hair should be damp, not drenched. 3. Let process for 10 minutes. DO NOT RINSE. 4. Apply N°.3 over hair with N°0 still applied. 5. Comb through and process for at least another 10 minutes. 6. Rinse, shampoo and condition. For best results, use N°.4 Shampoo and N°.5 Conditioner. *When used as a two-part system with N°.3 in just one use.