Olaplex No.4 Fine Bond Maintenance Shampoo for fine hair gently removes buildup, instantly doubles your hair’s volume, keeps it full all day, and repairs everyday damage after just 1 wash. A formula with flexible polymers helps add volume and lift hair at the roots. Bond-Building™ Technology restores and maintains damaged bonds for a stronger hair structure. Low molecular weight hyaluronic acid helps boost softness and hydration. This gives hair volume from the roots and keeps it clean, lightweight, and easy to style. The shampoo is suitable for straight, wavy, curly, or coily hair with a fine texture—and for all levels of porosity. Dermatologically tested. Vegan formula. Safe for color-treated and chemically treated hair.