Another intriguing finding is that quercetin may help prevent immune cells from releasing histamine, the chemical that initiates the itching, sneezing, and swelling of an allergic reaction. Based on this very preliminary research, quercetin is often recommended as a treatment for allergies and asthma. Sources Quercetin is not an essential nutrient. It is found in red wine, grapefruit, onions, apples, black tea and, in lesser amounts, in leafy green vegetables and beans. However, to get a therapeutic dosage, you ll have to take a supplement.
Quercetin supplements are available in pill and tablet form.
One problem with them, however, is that they don t seem to be well absorbed by the body. A special form called quercetin chalcone appears to be better absorbed. A typical dosage is 200 to 400 mg 3 times daily. Quercetin may be better absorbed if taken on an empty stomach. The most popular use of quercetin is as a treatment for allergic conditions such as asthma , hay fever , eczema , and hives.