Bladderwrack is type of brown seaweed named for the bladder-like air pockets along its leaves. It can be taken as an extract, pill, or powder.


There aren’t any advised doses for bladderwrack.

What Research Shows

There is not enough data to support that bladderwrack is helpful in treating health problems. We will review future studies as they are published.

Editorial process and description of evidence categories can be found at EBSCO NAT Editorial Process.

Safety Notes

It may be safe to take small doses of bladderwrack for a short period of time. It may contain iodine and add to thyroid problems and raise the risk of thyroid cancer. People with iodine allergy, thyroid problems, and women who are pregnant or breastfeeding should not take bladderwrack. Not enough studies have been done to say whether it is safe to take for a long period.


Talk to your doctor about any supplements or therapy you would like to use. Some can interfere with treatment or make conditions worse, such as:

  • People taking medicine to slow or prevent blood clots should talk to their doctor before taking bladderwrack. It may increase the risk of bleeding.

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This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.

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