Health Care Professional Information

Common Name

Sulfated alpha-L-fucan

Clinical Summary

Fucoidan is a sulfated polysaccharide found in the cell walls of many species of Brown seaweed. In vitro studies show that fucoidan has antitumor, antiangiogenic (2) (3) (4) (5) (6) (7), antiviral (15) (16), and immunomodulatory (17) effects. These effects are brought about by stimulating natural killer cells and by down regulating AP-I involved in cellular proliferation. Fucoidan also exhibited neuroprotective (11) (12), radioprotective (13), and antiulcer (14) properties but human data are lacking.
In other studies, fucoidan demonstrated anticoagulant (8) (9) and antithrombotic (10) activities, and can have additive effects when taken with anticoagulants.

Food Sources

Several species of Brown seaweed

Purported Uses
  • Allergies
  • Bacterial Infections
  • Hypertension
  • Immunostimulation
  • Inflammation
  • Viral infections
  • Alpha (1, 2) or Alpha (1, 3) 4-O-sulfated-L-fucose
  • Galactose
  • Xylose
  • Glucoronic acid
Mechanism of Action

Fucoidan has been shown to inhibit metastasis by preventing adhesion of tumor cells to the extracellular matrix. This is achieved by blocking the fibronectin cell-binding domain, necessary for formation of adhesion complexes (4). Fucoidan was also shown to induce apoptosis of human T-cell leukemia virus type I (HTLV-1) that causes Adult T-cell leukemia. It does so by inactivating NF-kB that regulates antiapoptotic proteins. It suppresses AP-I, a transcription factor involved in cellular proliferation and transformation (3). An vitro study showed that Fucoidan can suppress angiogenesis induced by Sarcoma 180 cells in mice (5). Fucoidan has immunomodulating effects and enhanced the activity of NK cells, which play a crucial role in mediating tumor cell death (2). The neuroprotective effects of fucoidan are attributed to its ability to suppress tumor necrosis factor-alpha (TNF-alpha)- and interferon-gamma (IFN-gamma)-induced NO production in C6 glioma cells (11) and to its antioxidative effects (12).


Because of its anticoagulant property (8) (9), fucoidan may have additive effects with anticoagulants such as warfarin and heparin.

Adverse Reactions

No adverse reactions have been reported from use of Fucoidan.

  1. Giraux JL, Matou S, Bros A, Tapon-Bretaudiere J, Letourneur D, Fischer AM. Modulation of human endothelial cell proliferation and migration by fucoidan and heparin. Eur J Cell Biol 1998; 77(4):352-359.
  2. Maruyama H, Tamauchi H, Hashimoto M, Nakano T. Antitumor activity and immune response of Mekabu fucoidan extracted from Sporophyll of Undaria pinnatifida. In Vivo 2003; 17(3):245-249.
  3. Haneji K, Matsuda T, Tomita M et al. Fucoidan extracted from cladosiphon okamuranus tokida induces apoptosis of human T-cell leukemia virus type 1-infected T-cell lines and primary adult T-cell leukemia cells. Nutr Cancer 2005; 52(2):189-201.
  4. Liu JM, Bignon J, Haroun-Bouhedja F et al. Inhibitory effect of fucoidan on the adhesion of adenocarcinoma cells to fibronectin. Anticancer Res 2005; 25(3B):2129-2133.
  5. Koyanagi S, Tanigawa N, Nakagawa H, Soeda S, Shimeno H. Oversulfation of fucoidan enhances its anti-angiogenic and antitumor activities. Biochem Pharmacol 2003; 65(2):173-179.
  6. Alekseyenko TV, Zhanayeva SY, Venediktova AA, et al. Antitumor and antimetastatic activity of fucoidan, a sulfated polysaccharide isolated from the Okhotsk Sea Fucus evanescens brown alga. Bull Exp Biol Med. 2007 Jun;143(6):730-2.
  7. Nagamine T, Hayakawa K, Kusakabe T, et al. Inhibitory effect of fucoidan on Huh7 hepatoma cells through downregulation of CXCL12. Nutr Cancer. 2009;61(3):340-7.
  8. Colliec S, Fischer AM, Tapon-Bretaudiere J, et al. Anticoagulant properties of a fucoïdan fraction. Thromb Res. 1991 Oct 15;64(2):143-54.
  9. Irhimeh MR, Fitton JH, Lowenthal RM. Pilot clinical study to evaluate the anticoagulant activity of fucoidan. Blood Coagul Fibrinolysis. 2009 Aug 18. [Epub ahead of print]
  10. Church FC, Meade JB, Treanor RE, Whinna HC. Antithrombin activity of fucoidan. The interaction of fucoidan with heparin cofactor II, antithrombin III, and thrombin. J Biol Chem. 1989 Feb 25;264(6):3618-23.
  11. Do H, Pyo S, Sohn EH. Suppression of iNOS expression by fucoidan is mediated by regulation of p38 MAPK, JAK/STAT, AP-1 and IRF-1, and depends on up-regulation of scavenger receptor B1 expression in TNF-alpha- and IFN-gamma-stimulated C6 glioma cells. J Nutr Biochem. 2009 Jul 1. [Epub ahead of print]
  12. Luo D, Zhang Q, Wang H, et al. Fucoidan protects against dopaminergic neuron death in vivo and in vitro. Eur J Pharmacol. 2009 Sep 1;617(1-3):33-40.
  13. Byon YY, Kim MH, Yoo ES, et al. Radioprotective effects of fucoidan on bone marrow cells: improvement of the cell survival and immunoreactivity. J Vet Sci. 2008 Dec;9(4):359-65.
  14. Choi JI, Raghavendran HR, Sung NY, et al. Effect of fucoidan on aspirin-induced stomach ulceration in rats. Chem Biol Interact. 2010 Jan 5;183(1):249-54.
  15. Lee JB, Hayashi K, Hashimoto M, Nakano T, Hayashi T. Novel antiviral fucoidan from sporophyll of Undaria pinnatifida (Mekabu). Chem Pharm Bull (Tokyo). 2004 Sep;52(9):1091-4.
  16. Hayashi K, Nakano T, Hashimoto M, Kanekiyo K, Hayashi T. Defensive effects of a fucoidan from brown alga Undaria pinnatifida against herpes simplex virus infection. Int Immunopharmacol. 2008 Jan;8(1):109-16.
  17. Raghavendran HR, Srinivasan P, Rekha S. Immunomodulatory activity of fucoidan against aspirin-induced gastric mucosal damage in rats. Int Immunopharmacol. 2011 Feb;11(2):157-63.

Consumer Information

How It Works

Bottom Line: Fucoidan has anticancer properties but it has not been studied in humans.Fucoidan is a complex polysaccharide found in many species of Brown seaweed. It can slow blood clotting. Laboratory studies suggest that it can prevent growth of cancer cells and has antiviral, neuroprotective, and immunomodulatory effects. But there are no human data. Because of its anticoagulant property, fucoidan may increase the side effects of “blood thinning” drugs.

Purported Uses
  • Immunostimulation
    Although in vitro data suggest a role for fucoidan in boosting host defense mechanisms, human data are lacking.
  • Anticancer
    Several in vitro and animal studies show that fucoidan has antitumor properties. Clinical trials have not been conducted.
  • Allergies
    There are no studies to support this use.
  • Lower blood pressure
    This use is not supported by clinical trials.
  • Decrease cholesterol
    There are no data to substantiate this claim.
  • Inhibit blood clotting
    Laboratory studies suggest that Fucoidan has anticoagulant and antithrombotic effects.
  • Antiviral
    Laboratory and animal studies indicate that fucoidan has antiviral properties. Human studies are needed.
Do Not Take If

Theoretically, fucoidan may have additive effects with anticoagulants such as warfarin and heparin.

Side Effects

No adverse reactions have been reported from use of Fucoidan.

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