Bladderwrack is a seaweed often used medicinally to treat a variety of conditions. In some parts of the world where is grows wild, such as Asia, it also constitutes part of the human diet. When used medicinally, people take capsules containing an extract of the plant. Tablets and topical preparations are also available. Because of the possibility of contamination from heavy metals in the waters where it grows, bladderwrack should be considered possibly unsafe when used as a supplement, according to the National Institutes of Health.
Thyroid Conditions
Because it contains iodine, bladderwrack is often used to treat and prevent thyroid conditions such as goiters and hyperthyroidism. Research shows that the seaweed does affect thyroid function, but because the amount of iodine in the plant varies, an effective dose is difficult to determine, according to the National Institutes of Health.
Blood Thinner
The fucans in bladderwrack have blood-thinning properties, according to the National Institutes of Health. Although the presence of fucans in the plant would theoretically make it useful as blood thinner, no human studies have been done to conclusively demonstrate this effect.
Cancer
Tests performed in laboratories and in animals have demonstrated that bladderwrack is among several species of brown algae that can inhibit the growth of or kill some cancer cells, according to the National Institutes of Health. However, human studies to this effect are lacking.
With regard to cancer prevention, bladderwrack and other seaweeds may be effective, according to the American Cancer Society. This is based on data showing that breast cancer rates in areas where seaweed is commonly eaten--such as Japan--are much lower than in North America, where seaweed is rarely consumed.
Laxative
A chemical in bladderwrack called algin may make it effective as a laxative, according to RXList. The algin in the plant allows the bowels to relax so stool can more easily pass through the colon.
Diabetes
Because bladderwrack appears to be effective in lowering blood sugar levels in animals, it may be useful as an alternative treatment for diabetes. However, human data supporting its efficacy for this use are not available, according to the National Institutes of Health.
Weight Loss
Bladderwrack and other seaweeds are often touted for their ability to aid in weight loss. However, the safety of using this products in this regard is not known and the effectiveness has not been proved, according to the National Institutes of Health.
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