A highly concentrated shampoo for medium-coarse hair that repairs everyday damage to strengthen, reinforce, nourish, and boost shine in 1 wash. Repair everyday damage in 1 wash. This #1 best-selling prestige shampoo* strengthens and reinforces bonds for more resilient hair, at a molecular level. The luxuriously nourishing and abundant lather gently cleanses and replenishes hydration- never stripping essential moisture-leaving hair soft and lightweight. Clinically proven to boost shine and reduce split ends and frizz. Formulated for straight, wavy, curly, and coily hair types with medium to coarse textures - plus all porosity levels. Dermatologist Tested. Vegan. Color-Safe and suitable for chemically treated hair. OLAPLEX Signature Scent Revitalize your senses with a bright burst of Grapefruit Zest, the crisp scent of Sugared Mint, Ginger, and a sophisticated, grounding base of Crushed Sage. PRO TIP: For complete repair from all types of damage, use Nº. 3PLUS Complete Repair Treatment weekly. *Source: Circana, LLC, U. S. Prestige Beauty Total Measured Market, Prestige Brand Classification, Daily Rinse Shampoo and Conditioner Product Dollar and Unit Sales, January - December 2024 **When used as a system with Nº. 5 Bond Maintenance™ Strengthening Conditioner. | Olaplex No. 4 Strengthening Shampoo, 100 ml | Dermstore