All Olaplex products contain patented technology, strengthening fragile bonds with every step of the routine for the healthiest hair possible. The best-selling shampoo, is now formulated to celebrate the beauty of blonde. Olaplex No.4 Bond Maintenance Shampoo cleanses while adding hydration and repair. The newest addition to the family, Olaplex No.4-P maintains all the benefits of the original and deposits just the right amount of tone to neutralize any unwanted warmth between salon visits.