Fucoidan is a type of polysaccharide found in seaweeds that has been researched for its anticancer effects. It may benefit those with osteoarthritis and cancer patients undergoing chemotherapy treatment. Read on to see the benefits and mechanisms of fucoidan. 

What Is Fucoidan?

Fucoidan is a complex sulfated polysaccharide derived from rich sources such as bladderwrack, other brown algae, echinoderms, and seagrasses [1].

Fucoidan exhibits many different biological properties [2, 3, 4, 5, 6, 7]:

  • Anti-inflammatory
  • Anti-coagulant (prevents blood clotting)
  • Anti-thrombotic (reduces the formation of clots)
  • Anti-angiogenic (reduces the growth of new blood vessels)
  • Anti-viral
  • Anti-tumor
  • Anti-oxidant

Research in marine food sources has helped reveal many potential remedies for an array of health issues – most being attributable to the presence of fucoidan.

Mechanisms of Action

Fucoidan triggers programmed cell death by decreasing the release of three metalloproteinase enzymes: MMP-1, MMP-3, and MMP-9 [8].

Fucoidan decreases NF-kappaB binding activity, p65 nuclear movement of proteins from the cellular fluid to the nucleus, and IκB-α degradation, which prevents inflammation [8].

Fucoidan stimulates an increase in natural killer (NK) cells and a decrease of transcription factor AP-I, which is involved in cellular growth and division. Fucoidan also kills T-cell leukemia virus type I (HTLV-1) by inactivating NF-kB, a regulator of antiapoptotic proteins [9, 10].

Fucoidan activates caspases 8 and 9, which are enzymes involved in programmed cell death [11].

Benefits of Fucoidan and Fucoidan-Rich Foods

1) May Help with Osteoarthritis Symptoms

In a pilot study of 12 people with osteoarthritis (OA) of the knee, 100 mg of a fucoidan supplement given for three months reduced symptoms of arthritis by 18% and 1,000 mg of fucoidan reduced symptoms by 52% [12].

Another study (DB-RCT) of 122 people with OA of the knee and hip, 255 mg of fucoidan from bladderwrack showed no difference in reduction of arthritis symptoms compared to placebo [13].

2) May Help Fight Cancer

Fucoidan fight cancer by immune cell activation and increased production of anticancer cytokines [14, 15, 16].

Fucoidan extracted from bladderwrack cause cell death in various human cancer cells, including leukemia, breast cancer, stomach cancer, lung cancer, prostate cancer, and liver cancer cells [17, 18, 19, 20, 21, 22, 11].

Fucoidan blocked cell growth, caused programmed cell death, and suppressed formation of new blood cells in thyroid cancer cells [23].

The disease control rate (DCR) is the percentage of patients who have achieved complete response, partial response, and stable disease from a therapy. In a study (DB-RCT) of 54 patients with colorectal cancer, 4,000 mg fucoidan powder in addition to chemotherapy resulted in a DCR of 92%, compared to 69% in the placebo group [24].

3) May Prevent Clots

In a cell study, fucoidan increased the activity of proteins that block the coagulation process [25].

In a pilot study of 20 volunteers, 2,250 mg fucoidan for 12 days moderately decreased clotting ability by interfering with the final stage of the coagulation process [26].

4) May Fight Viruses

Fucoidans protect against many different species of viruses. Evidence for the effect of fucoidans against viruses include:

  • Fucoidan strongly inhibited influenza A infection in mice [27].
  • Fucoidan prevented herpes from entering cells in test-tube studies [28].
  • Fucoidans stop viruses from replicating and increase immune defense functions [29].
  • Fucoidan inhibited type 2 dengue virus in cell studies [30].
  • Fucoidan blocked HTLV-1 (human T lymphotropic virus type-1) infection in cell studies [31].
  • Fucoidan may be capable of preventing HIV infection by blocking the enzymes needed by the virus to replicate [32].
  • Fucoidan demonstrated potent antiviral activity against herpes of all types: simplex virus type 1 (HSV-1), HSV-2, and human cytomegalovirus [33].

5) May Protect the Brain

Fucoidan delayed the onset of disease in mice infected with scrapie, a disease that leads to mitochondrial dysfunction in the brain [34, 35].

In a rat brain model, fucoidan prevented the death of neurons caused by β-amyloid plaques, which are involved in Alzheimer’s disease [36].

Fucoidan prevented overactivation of microglia that may lead to neurodegeneration [37].

Treatment with fucoidan reduces the encephalitogenic response (brain swelling and spinal cord swelling) in encephalomyelitis [38].

6) May Protect Against Radiation

Fucoidan provided protection from radiation in cells and in mice [39].

7) May Protect Against Chemotherapy

In mice given chemotherapy, fucoidan prevented gut inflammation and increased the length of villi in the gut [40].

8) May Protect the Stomach

Fucoidan inhibited Helicobacter infections in the stomach by preventing the bacteria from sticking to gut walls [41].

In rats given aspirin to cause ulcers, fucoidan prevented the ulcers from developing [42].

9) Protects the Liver

Due to fucoidan, bladderwrack helps to protect against chemically-induced excess scarring of the liver [43, 44].

Fucoidan reduced alcohol-induced fatty liver disease in rats [45].

10) May Fight Malaria

Fucoidan helped fight malaria infection in cell studies and in mice [46].

11) May Help Prevent Kidney Stones

Kidney stones can be caused by high levels of oxalate. In rats with excessive oxalate in their urine, fucoidan normalized oxalate levels. Fucoidans also improved antioxidant status and reduced the risk of developing stones [47].

12) May Prevent Obesity

Fucoidan increased the activity of the enzyme that breaks down fat (lipase). Fucoidan also blocks glucose uptake into fat cells, which helps with fat loss [48].

Mice exposed to a high-fat diet gained less weight when fucoidan was included in their diet [49].

Side Effects, Limitations, Drug Interactions, and Dosage

Side Effects

Fucoidan appears to be very well-tolerated, with no reported side effects.

Carotenodermia, oranging/yellowing of the skin, may arise from excessive dietary intake of seaweeds [50].

Limitations and Caveats

Most of the studies on fucoidan are in animals or isolated cells and there is a lack of clinical trials to support the existing research. Further clinical trials are needed to confirm if fucoidan benefits humans. Caution should be taken when applying this research to use in humans.

Drug Interactions

Because fucoidan may be an anticoagulant (clot preventative), caution should be taken when using it with other anticoagulants such as warfarin or heparin [25, 26].

Dosages For Fucoidan and Fucoidan-Rich Supplements

Dosage for fucoidan ranges from 100 mg to 4,000 mg twice daily.

Dosage toward the lower end of that range may be effective for osteoarthritis symptoms [12].

Dosage towards the higher end may be more effective as an adjuvant cancer therapy.


“This product has improved my ability to recover. Stressors, which would have resulted in fatigue, are no longer as big an issue.”

“If you are struggling with anything cancer-related, I would not hesitate in recommending this one of a kind supplement.”

“Bought this for a lung cancer patient, because heard of some positive reports of fucoidan on cancer treatment. Taken 10 pills per day for over 4 months. Recent CT scan showed further dispersion of cancer cells.”

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About the Author

Will Hunter

BA (Psychology)
Will received his BA in Psychology from the University of California, Los Angeles. 
Will's main passion is learning how to optimize physical and mental performance through diet, supplement, and lifestyle interventions. He focuses on systems thinking to leverage technology and information and help you get the most out of your body and brain.

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