Quercetin is a plant flavonol from the flavonoid group of polyphenols. It is found in many fruits, vegetables, leaves, seeds, and grains; red onions and kale are common foods containing appreciable amounts. In addition to functioning as a flavonoid, quercetin is also a phytoestrogen. This means that, in women, it can weakly bind to the body’s oestrogen receptors and mimic the effects of the hormone oestrogen on the body. YourHealthBasket offers Quercetin as a stand-alone supplement, in some multivitamin complexes or in combination with other nutrients, for example Vitamin C, which has been shown to improve the gut’s absorption. Quercetin is typically not well absorbed by the body making bioavailability quite low. This can be overcome by taking a liposomal supplement or in dietary terms, ingesting red onions and kale alongside high-fat foods. You should be able to get plenty of quercetin from eating a diet rich in fruit and vegetables. However, if you prefer to take a supplement, doses of 500-1000 mg a day are considered safe. There's a lot of research available online and multiple clinical studies which we encourage you to seek out and increase your own knowledge to find out if this particular flavonol is the one for you.