Is Bladderwrack Effective for Weight Loss?

A small spoonful of bladderwrack seaweed.
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Ultimately, the key to weight loss is to burn more calories than you take in. You need to reduce your total calories by 3,500 to lose 1 lb., and a safe amount of weight to lose is 1 to 2 lbs. a week. This is best achieved through a combination of diet and exercise. Nonetheless, people take supplements in the hopes of boosting their weight loss. Bladderwrack is one such herbal supplement, although research does not support its supposed weight loss effects.



Bladderwrack, a form of seaweed, is used medicinally for thyroid concerns, arthritis and joint pain, obesity, iodine deficiency, constipation and a number of other conditions. It is also used topically for the skin to treat insect bites, aging, burns and skin diseases. However, there is not enough evidence to support the use of bladderwrack for any medicinal use. MedlinePlus claims that seaweed hasn't been effective in helping people lose weight or maintain a healthy weight.


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Bladderwrack has been used for obesity because it is believed to stimulate your thyroid gland to regulate weight. It was discovered for this purpose in 1862 by Dr. Duchesne-Duparc, who noticed the weight loss when he was attempting to treat chronic psoriasis with bladderwrack. The weight loss resulted from the thyroid gland being stimulated.

Thyroid and Weight

The thyroid gland helps control your metabolism to maintain a healthy weight. If you do not produce enough thyroid hormone, as is the case with hypothyroidism, your body slows down and your appetite can change, resulting in weight gain. Iodine, which is found in bladderwrack, might help this condition, but it depends on the cause of your hypothyroidism. Talk to your doctor before taking it for this, as it can cause hypothyroidism as well.



There are possible side effects from bladderwrack. It sometimes contains high amounts of iodine, which an excess of can cause goiter and thyroid problems, including thyroid cancer. Bladderwrack can contain heavy metals from the water that can be toxic. Avoid bladderwrack if you are infertile, pregnant or nursing, scheduled for surgery or have an allergy to iodine. Bladderwrack can also interfere with medications for the thyroid or medications to slow blood clotting.




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