Cantu Flaxseed Sulfate Free Shampoo Remove unsightly product buildup and enjoy beautifully clean curls with Cantu’s Flaxseed Smoothing Shampoo! The flaxseed helps reduce breakage, repairs damaged curls, and minimizes frizz to reveal beautiful hair with a natural shine. Allow Cantu to restore your hair’s authentic beauty with a carefully-curated formula designed for curly, coily and wavy hair.