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Quercetin: More Energy, Fewer Allergies

This powerful antioxidant can boost stamina and reduce blood pressure

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This powerful antioxidant can boost stamina and reduce blood pressure


Quercetin (pronounced kwair-sih-tin) is an antioxidant flavonoid found in many different fruits and vegetables. Supplements have been found helpful in improving exercise stamina and prostatitis in people. Experimental evidence suggests that quercetin may be helpful in reducing blood pressure, pollen allergies, and possibly cancer risk.


Chemically, quercetin is closely related to rutin and quercitrin, two other flavonoids. Quercetin lacks a sugar molecule that is attached to these other flavonoids. When rutin and quercitrin are digested, intestinal bacteria remove the sugar molecule.


In addition to being an antioxidant, quercetin also has anti-inflammatory properties. It may alter the interaction between two key types of immune cells, Th1 and Th2.


Quercetin has some striking health benefits.

Exercise stamina.

Recent research on trained athletes and people just beginning a regimen of physical activity showed that supplemental quercetin can increase endurance. People taking 1,000 milligrams of quercetin daily had increased numbers of mitochondria in their muscle cells, which would help in energy production. In addition, quercetin may reduce the risk of flu after strenuous exercise.

In one study, J. Mark Davis, PhD, and his colleagues at the University of South Carolina, Columbia, tested 12 sedentary subjects’ endurance on an exercise bicycle. After taking quercetin supplements-500 milligrams twice daily for one week-the subjects’ lung function and stamina improved. A separate study, conducted at Appalachian State University in Boone, North Carolina, found that 1,000 milligrams of quercetin led to better treadmill workouts after only two weeks.


Nonbacterial prostatitis causes severe pelvic pain and is difficult to treat, but quercetin may be of tremendous benefit. Researchers at the Institute for Male Urology, in Los Angeles, gave men with prostatitis 1,000 milligrams of quercetin daily for a month. Two-thirds of the men had at least a 25 percent reduction in symptoms. When the doctors added bromelain and papain supplements to enhance quercetin absorption, 82 percent of the patients got better.

Pollen allergies and asthma.

Alternatively minded physicians have long suggested quercetin supplements to help ease pollen allergies. There’s good reason for the recommendation. A Japanese study of 20 people with pollen allergies found that quercetin supplements reduced eye irritation and itching. The subjects were given 200 milligrams of a proprietary form of quercetin for eight weeks. Meanwhile, an animal study found that quercetin significantly reduced asthmatic reactions. Still other research has found that quercetin reduces the reactivity of mast cells, which release histamine during allergic reactions.

Blood pressure.

Some evidence suggests that quercetin supplements might help lower blood pressure. Researchers at the University of Utah found that people with mild hypertension improved after taking 730 milligrams of quercetin daily for 28 days. Quercetin had no effect on people with normal blood pressure.


The richest food sources of quercetin are capers, lovage (also known as sea parsley), buckwheat, and apples. It’s also concentrated in honey and the outermost rings of red onions.


When shopping for quercetin, look for supplements in capsules. Some quercetin-containing sports drinks contain either too little quercetin or too much sugar.


To ease pollen allergies, start with 250 milligrams of quercetin daily. If it doesn’t alleviate symptoms, slowly increase the daily amount to 1,000 milligrams. For prostatitis, take 1,000 to 2,000 milligrams daily. To increase exercise endurance, take 1,000 milligrams daily.

The doctor suggested quercetin supplements. Jennifer started taking 250 milligrams of quercetin with each meal and noticed an improvement in her allergies. After reporting back to her doctor, he suggested that Jennifer add bromelain and papain, two digestive enzymes that help the body absorb quercetin. The addition of these supplements led to a significant reduction of Jennifer’s allergies.

Did you know?
Research indicates that quercetin may slow the growth of, or even induce the death of, cancer cells. A form of quercetin is now being used experimentally to treat some cancers.

Quercetin supplements lessen the effect of pollen allergies:

Jennifer suffered from pollen allergies and occasional asthma episodes throughout the year. Medications made her drowsy, so she saw a naturopathic physician to investigate natural remedies that might help.

Product examples

Jarrow Formulas Quercetin 500 capsules provides 500 mg of the flavonoid in just one capsule.
Twinlab Quercetin+C combines noncitrus vitamin C (1,400 mg) with 500 mg of quercetin in two capsules.
Irwin Naturals Aller-Pure softgels help alleviate allergy symptoms and boost immunity with a mix of herbs and nutrients, including 300 mg of quercetin.
Reserveage Organics Ultimate Antioxidant blends the powerful antioxidant resveratrol from red grapes with 100 mg of quercetin, pomegranate, green tea, cocoa, and grape seed extract.