Quercetin is a yellow flavonoid that occurs in small amounts in foods like capers, onions, and kale. It also naturally occurs in plants, like Ginkgo biloba
, St. John's wort
, and sea buckthorn
As discussed in more detail in our Quercetin Supplements Review
(which includes our Top Picks
), preliminary evidence suggests that quercetin may be helpful to men with prostatitis, which is why it is added as an ingredient in some prostate supplements
, although these combinations have typically not been clinically tested. It may also have modest benefit in rheumatoid arthritis, and one small clinical study found that quercetin helped improve word-recall memory when taken with resveratrol
Although quercetin is commonly promoted for a wide range of other uses - including allergies, asthma and cardiovascular disease - the evidence supporting these uses is limited.