A "best sulfate-free shampoo for colored hair" is a hair care product specifically formulated to preserve the vibrancy and longevity of chemically treated hair.
Sulfates, which are harsh detergents found in traditional shampoos, can strip away the protective coating that surrounds colored hair, making it dry, dull, and prone to fading. Sulfate-free shampoos gently cleanse the hair without damaging the color, maintaining its brilliance and longevity.