Olaplex Intensive Bond Building Hair Treatment N°0 is an intensive repair booster that is absorbed by the hair and prepares it for treatment with Olaplex Hair Perfector N°3. As a 2-step home treatment, N°0 and N°3 repair broken disulfide bonds in the hair and sustainably strengthen the hair structure. Scientifically proven: 68% more repair and 3x more strengthening of the hair. It acts like a primer and prepares the hair for the restorative treatment. It repairs hair damage caused by chemical treatments, styling, heat (such as straightening and blow-drying), sunlight, and more. Suitable for all hair types. Enough for approximately 4-6 applications.