Introducing Nº4 Bond Maintenance Shampoo By Olaplex, A Restorative Solution Designed For Damaged, Compromised, Or Chemically Treated Hair. Olaplex Continues Its Renowned Professional Treatment Series With A Two-step System That Allows You To Restore Your Hair From The Comfort Of Your Home. This Shampoo And Its Complementary Conditioner Work In Conjunction With Steps 1 And 2 (professional Services In Salons) And Step 3 (at-home Maintenance). Suitable For All Hair Types And Textures, This Shampoo Features The Brand's Innovative Bond Multiplier: Bisaminopropyl Diglycol Dimaleate. This Active Ingredient Effectively Reconnects The Sulfur And Disulfide Bonds In The Hair's Keratin That Can Break Due To Harsh Treatments Altering Its Shape Or Color. It Offers Daily Hydration Without Weighing The Hair Down, Repairs Split Ends, And Strengthens Hair With Each Application. Additionally, It Restores Flexibility And Manageability While Enhancing Softness And Shine. Olaplex's Formula Is Vegan, Free From Parabens, Sulfates, And Gluten, And Is Cruelty-free.