Ecklonia Cava Extract from Swanson GreenFoods Formulas is produced from a type of brown algae grown off the coast of Korea and Japan. It features a unique form of polyphenols called phlorotannins that are chemically distinct from all land/plant based polyphenols. Ecklonia Cava is the star of this class of algae-based antioxidants, and it may offer stronger antioxidant benefits than land-based sources like green tea or resveratrol (potentially up to 2 or 3 times the strength). Plus, Swanson 99.9% pure Ecklonia Cava is the purest water-based extract you can buy.