Several nutraceutical products have been developed from Fucus vesiculosus, a brown edible seaweed, rich in dietary fiber and polyphenolic antioxidants (phlorotannins). The aim of this work was to compare the antioxidant capacity and polysaccharide composition of raw Fucus with those of some common commercial nutraceuticals. All tested products contained a high percentage of dietary fiber (45-59%), raw Fucus powder being the sample with the highest content. Also, raw Fucus powder exhibited significantly higher antioxidant capacity (determined by FRAP, ABTS and ORAC assays) than the commercial fucoidans and commercial antioxidant extracts. Polyphenols (phlorotannins) seem to be the main contributors to Fucus' antioxidant capacity in both raw powder and commercial fucoidans.