What it is: A multi-action shampoo for stronger, defined, and more hydrated coils, curls, and waves in one use. Hair Texture: Wavy, Curly, and Coily Hair Type: Fine, Medium, and Thick Hair Concerns: - Curl-Enhancing - Damage, Split Ends, and Breakage - Dryness Key Benefits: - Instantly strong, infinitely defined, and seven-day hydrated curls - Reduces breakage and protects length - Cuts frizz in half, even in high humidity Highlighted Ingredients: - Patented 3D Bond Shaper Technology: Builds disulfide bonds to repair, strengthen, and define coils and curls. - Hydra-Define Technology: Neutralizes damage, seals cuticles to lock hydration, and blocks humidity. - Natural Oil Blend: Nourishing avocado and sunflower oils add moisture, softness, and definition. Ingredient Callouts: Free of parabens, phthalates, mineral oil, and sulfates SLS & SLES. It is also cruelty-free. What Else You Need to Know: No.4 CURL Shampoo works on a molecular level to strengthen, define, and hydrate curls and coils, cutting frizz in half and protecting length over time. The silky cream-gel prevents tangles and removes buildup without stripping for seven-day hydrated curls. This shampoo is great for all porosity levels and is color safe. Fragrance Description: The Olaplex Signature Scent, Reimagined: Revitalize your senses with elevated notes of crisp and invigorating sugared mint complemented by a bright burst of grapefruit zest and ginger and a sophisticated, grounding base of crushed sage. Clinical Results: When N°.4CURL and N°.5CURL are used as a system: - 50% less frizz, even in high humidity Based on a 2-week, 75-person consumer study: - 96% agree hair was easier to detangle In studies: - 7 days of hydrated curls - Stronger hair and less breakage - Defined curl pattern