A highly moisturising, reparative shampoo that leaves hair easy to manage, shiny and healthier with each use. N?4 is colour safe, sulphate free, and proven to reduce breakage and strengthen all types of hair. Key benefits repairs and maintains bonds within the hair eliminates frizz and flyaways reduces breakage ph balance 6 6.5 pro tip a little goes a long way! Start with a coin size squeeze and work your way up if needed. To use apply and massage product throughout hair. Rinse product from hair. Follow with olaplex n?5 bond maintenance conditioner sold separately. Where concentrate on roots. When formulated for daily or every wash use. For all hair types, especially those needing clarifying or oil control. Olaplex products are thoroughly tested in house and by independent third party laboratories for safety and efficacy. This product testing includes the industry standard human repeat insult patch test hript, which tests for skin irritation or sensitivity. All olaplex products have passed the hript, meaning the products show no signs of causing irritation, inflammation, or sensitivity.