Doctor's Best Fucoidan 70% contains the glyconutrient 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.