Unclear
Sea moss
Irish moss gels, powders and capsules. Herbs & mushrooms.
Safety: It's easy to get too much iodine, which can upset the thyroid, and products can carry heavy metals.
- 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 studied
What the evidence shows
No studies show sea moss helps prevent or treat cancer, and experts quoted by National Geographic say most evidence for its claimed benefits is early. Commercial products vary widely in iodine and rarely say how much they contain, and seaweeds can accumulate arsenic, mercury and lead.
What to do
Skip it for cancer. If you have a thyroid condition, ask your doctor before using it.
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.