Best fucoidan 70% contains the gluconutrient fucoidan derived from brown algae. seaweeds are a part of the diet in many cultures and fucoidan-containing species have been used traditionally for a variety of therapeutic purposes. fucoidan contains an abundance of immune-modulating constituents known as polysaccharides.* these unique and complex sulfated polysaccharides are not found in other seaweeds or land plants, and have been shown to mediate a variety of significant biological effects on mammalian cells in laboratory research.* research also suggests that fucoidan may possess significant antioxidant activity.*