Fucus vesiculosus, a type of seaweed known as bladderwrack, has a role in alternative medicine for treating many health disorders. Fucus vesiculosus is available as a supplement in tablets, capsules and extract, and people also use this vegetable in salads, soups and stews. As of 2010, research is lacking on its effectiveness for any health problems, according to the U.S. National Institutes of Health (NIH), because most studies are laboratory-based and have not involved humans. People should be cautious about taking Fucus vesiculosus as a supplement or consuming it in large amounts, because it has a high iodine content that can cause negative side effects and is often contaminated with heavy metals.

Hypothyroidism

Because Fucus vesiculosus contains iodine, it might be useful for treating underactive thyroid (hypothyroidism) caused by low iodine levels in the body. The University of Maryland Medical Center (UMMC) cautions that most cases of underactive thyroid in developed countries are not due to iodine deficiency, and people should consult a doctor before using Fucus vesiculosus for this purpose. Too much iodine can actually cause hypothyroidism and also can lead to an overactive thyroid (hyperthyroidism).

Anti-Estrogenic Benefits

Fucus vesiculosus and other types of seaweed show anti-estrogenic effects, according to the Memorial Sloan-Kettering Cancer Center (MSKCC), which may account for the lower risk of estrogen-related cancers in Asian populations. Fucus vesiculosus also may improve some problems with menstruation. During a study published in the August 4, 2004 issue of BMC Complementary and Alternative Medicine, authors administered Fucus vesiculosus to three pre-menopausal women experiencing abnormal cycles or other menstrual-related problems. Fucus vesiculosus appeared to lengthen the menstrual cycle and had anti-estrogen effects. Excess estrogen is associated with premenstrual fluid retention, weight gain, mood swings, headaches and menstrual cramps.

Anti-Cancer Potential

Several types of seaweed, including Fucus vesiculosus, show potential for being able to prevent and treat cancer, based on animal and laboratory studies, according to the NIH. Fucus vesiculosus may suppress the growth of cancer cells.

Blood Sugar Reduction

Fucus vesiculosus extract may reduce blood glucose levels, making it useful for treating people with diabetes. This potential use is only based on animal research, however, according to the NIH, and reliable human studies are lacking.

Cardiovascular Effects

Fucus vesiculosus contains fucans and fucoidans, components which show anticoagulant, or blood-thinning, properties in laboratory research, according to the NIH. Additionally, fucosterols in this substance reduce plasma cholesterol levels, as explained by the MSKCC. The plant may lower high blood pressure because it inhibits angiotensin-I-converting enzyme. Medications with this effect, called ACE inhibitors, are commonly used to treat high blood pressure.

Anti-Aging Effects

A study published in the January/February 2002 issue of the Journal of Cosmetic Science determined that Fucus vesiculosus extract possesses anti-aging properties and should be useful as a cosmetic ingredient. The study found that a gel containing 1 percent Fucus vesiculosus extract applied to cheek skin twice daily for five weeks decreased skin thickness and improved elasticity when compared with control substances. The authors note that cheek skin thickness normally increases with age, whereas elasticity decreases.