What forms of flavonoids are found in dietary supplements?

By far the most common supplemental form of flavonoids are the citrus flavonoids quercetin, rutin, and hesperidin. Of these three, the most common is quercetin.Doses in commonly sold supplements usually range from 25-200 milligrams, although clinical studies using flavonoids often use much higher level interventions in the 500-3,000 milligram range.