Quercetin
the flavonoid in onions, capers and apples, in pills. Herbs & mushrooms.
- 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
Memorial Sloan Kettering says there's considerable lab data, but it's still unclear from clinical trials whether quercetin has anticancer effects in the body, and the few studies are mixed. A review found that the quercetin in a typical diet may not lower ovarian cancer risk.
What to do
Eat the foods. Ask your care team before taking pills, especially during chemotherapy or with a blood thinner.
Sources
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.