Unclear
Bladderwrack
Fucus seaweed, often in kelp or thyroid blends. Herbs & mushrooms.
Safety: Bladderwrack from polluted waters may contain arsenic, cadmium and mercury, which can damage the kidneys.
- Verdict
- UnclearThere isn't enough human evidence to say either way.
- How sure
- Rung 1 · UnprovenLab or animal data only, or never directly tested in people.
The rung shows how sure the science is, not how big the effect is. How to read these ratings
Cancers affected
None shown in people
What the evidence shows
Anticancer effects have been seen only in lab studies, and Memorial Sloan Kettering says claimed benefits haven't been confirmed in clinical studies. It is rich in iodine, and it may affect how some medicines are processed.
What to do
Don't take it for cancer. Tell your care team if you use it, because of possible drug interactions.
Sources
To take it to your doctor, print this page.
Spotted an error? Tell us and we’ll check it against the sources.
Related
Every supplement we rated, or follow one cancer step by step: breast cancer, colorectal cancer, lung cancer and prostate cancer.