If you’re looking for the best quercetin supplements to buy this year, then you’ve come to the right place.
You can also get more info by jumping to our Quercetin Supplements Guide.
Top 10 Quercetin Supplements
|#1||NOW Foods Quercetin W/Bromelain||More Info|
|#2||Jarrow Formulas Quercetin||More Info|
|#3||Doctor’s Best Quercetin/Bromelain||More Info|
|#4||Solgar Quercetin Complex with Ester-C||More Info|
|#5||Source Naturals Activated Quercetin||More Info|
|#6||Life Extension Optimized Quercetin||More Info|
|#7||Solaray Quercetin Capsules||More Info|
|#8||Amazing Nutrition Amazing Formulas Quercetin||More Info|
|#9||Pure Encapsulations – Quercetin||More Info|
|#10||Thorne Research – Quercetin Phytosome||More Info|
What is Quercetin?
Quercetin is a flavonoid, a pigment that imparts colors to flowers, fruits and vegetables. Flavonoids are antioxidants, compounds that neutralize free radicals and protect your body against free radical-related damage.
Quercetin is as an added ingredient in pre-packaged foods, beverages and sports supplements. It may be manufactured as a standalone supplement or paired with the digestive enzyme/antioxidant bromelain, with vitamin C or with other nutrients.
Quercetin supplements come in every imaginable, available delivery system, including capsule, tablet, caplet, powder, ready-to-drink concoctions, edible solids (gummies, for example), and vegetarian- and vegan-friendly (devoid of animal products, such as animal gelatin capsules.)
Quercetin is so common and abundant in the foods you eat, your average daily consumption might already fall between roughly 5 to 40 milligrams, according to WebMD. If you consume lots of fruits and vegetables, your average daily consumption might be upwards of 500 milligrams.
Ten common natural dietary sources of quercetin include:
- Black and green tea
- Red kidney beans
- Red Delicious apples
- Red onions
- Olive oil
- Red Wine
Quercetin also occurs naturally in certain kinds of honey from various plants and is 79 percent more abundant in organically grown tomatoes than conventionally grown tomatoes. Quercetin exists in fat-soluble and water-soluble forms. Quercetin-chalcone and dihydroquercetin are examples of the latter.
Both forms share the same qualities and health benefits, although research confirms that fat-soluble quercetin specifically protects red blood cells against oxidative damage.
Benefits of Quercetin
As mentioned above, quercetin is an antioxidant. Antioxidants are substances that scavenge free radicals throughout your body. Free radicals are natural byproducts of metabolism, exercise, stress, the effects of poor diet and pollution.
Free radicals are atoms possessing unpaired electrons. Antioxidants are the only substances in nature that can donate electrons without themselves becoming free radicals. Long term free radical damage is a primary, underlying cause of disease, malignancy, everyday sickness and premature aging.
Quercetin minimizes inflammation and allergic reactions. The mechanisms and pathways by which quercetin achieves this aren’t known precisely, and most corroborating evidence is either anecdotal or restricted to reputable scientific studies involving lab animals or test tube cultures.
Inflammation occurs when your body’s white blood cells release chemicals into tissues or into your blood to combat a foreign substance. Similarly, allergic responses, such as sneezing, itching, bumps and watery eyes, occur when mast cells (white blood cells) release histamines into your blood to attack infection or an infiltration of foreign bodies.
Quercetin stops white blood cells from releasing excessive amounts of chemicals and histamines that cause swelling, inflammation and allergy symptoms. Anecdotal evidence supports the efficacy of quercetin as a non-toxic antihistamine strategy in the prevention of seasonal allergic reactions to pollen and even common reactions to dust and cat dander.
Other studies confirm that quercetin’s anti-inflammatory powers extend to such conditions as prostitis, interstitial cystitis and rheumatoid arthritis. Quercetin may reduce your chances of developing heart disease by lowering your bad cholesterol.
Other evidence implies a link between high quercetein supplementation and a reduction in high blood pressure as well as the risk of cancer, reports the University of Maryland Medical Center.
Quercetin potentially enhances and diminishes the effectiveness of certain chemotherapy drugs, states the Penn State Health Milton S. Hershey Medical Center. Consequently, its usefulness in fighting cancer is still hotly debated as of 2017. Some doctors advise against ingesting antioxidants with chemotherapy drugs exactly for this reason.
One study found that quercetin supplementation combined with doxorubicin, a chemotherapy drug prescribed to counteract cancerous tumors, augmented the drug’s beneficial effects on breast cancer cells.
Another study showed that quercetin stacked with cisplatin, a chemotherapy drug, inhibited the drug’s therapeutic effects on ovarian cancer cells. Quercetin increases the absorption of green tea catechins and resveratrol, two antioxidants with their cancer-fighting powers.
According to Examine.com, a consistent quercetin dose of 20 milligrams for every 2 pounds of body weight protects testicles from damage related to Dioxins. Dioxins are persistent environmental pollutants used in paper bleaching and herbicide production.
A dose of 4 grams of quercetin per 2 pounds of bodyweight taken for 20 days raised testosterone levels in rats during one study. The study in question solely used onion juice, a rich natural source.
Conversely, similar studies found that highly concentrated versions of quercetin compel the body to aromatize testosterone at a rate of four times average. During aromatization your body transforms testosterone and anabolic steroids into estrogen. Serious lifters may want to restrict quercetin supplementation to some degree or avoid it.
Are There any Side Effects?
Quercetin is generally safe. However, there are side effects related to high daily intake. Common daily oral dosages are roughly 1,000 milligrams or less broken up into at least two doses.
There are no established optimal dosages. Product purity and potency varies between brands, making it more difficult to accurately gauge safe dosages on a case-by-case basis.
Long term side effects of usage at 1,000 milligrams twice daily are unknown. Dosing intravenously seems to carry greater risk. Some known side effects are:
- Upset stomach
- Tingling in the arms and legs
- Kidney damage
Doctors do not advise pregnant women to take quercetin. Increased appetite and food consumption paired with quercetin supplementation among pregnant women might lead to dangerously high exposure and subsequent toxicity.
Quercetin inhibits an important liver enzyme, CYP3A4. CYP3A4 factors directly into the metabolism of prescription antibiotics and drugs, such as cyclosporine.
Inhibited CYP3A4 and impaired liver function may lower the critical amounts of these drugs in your blood or change their effects entirely. With other substances, such as digoxin and fluoroguinolones, quercetin seems to either increase each drug’s inherent risks or reduce their efficacy, as noted above.
Quercetin may interact negatively with anticoagulants/blood thinners like:
- Clopidogrel (Plavix)
Quercetin causes corticosteroids to remain in your body longer than usual. Exposure to corticosteroids for any period increases the possibility of certain side effects:
- High blood pressure
- Fluid retention
- Weight gain
- Thinning bones and fracture
Except for quercetin’s negative interactions with certain prescription drugs, all of these side effects pertain to high dosages of quercetin taken over extended periods. There are little to no side effects when you take quecetin appropriately and in safe dosages.
How to Take Quercetin
Oral ingestion is the safest and most common way to administer quercetin. Pill and capsule are widely available forms, usually stacked with another vitamin, antioxidant or flavonoid.
Recall that there are bulk powdered versions of quercetin available as well. You can transfer powder to capsule sizes of your choice or mix it with smoothies, workout drinks and nutritional beverages.
For general physical maintenance and health, Dr. Andrew Weil recommends 100 to 250 milligrams three times daily.
If you’re struggling with hay fever, other seasonal allergies or reactions to cat dander, shoot for about 800 milligrams daily. Divide the dose into two equal amounts between meals.
Dr. Weil approves of quercetin supplementation for children at half the adult dosage and endorses easy-to-swallow coated tablets. Weil suggests avoidance of powdered quercetin, perhaps due to its higher variability and potency.
What to Look For in a Good Quercetin Product
There are no standardized formulations of quercetin even from top manufacturers, so product bench markers do not exist that definitively reference value and purity. Instead, appraise the manufacturer of a particular quercetin product to deduce the product’s quality.
Here are some encouraging qualities to look for in a supplement manufacturer:
- Positive reputation among customers
- Majority of customer reviews are favorable
- Awards, citations and recommendations from trusted professionals, the media and industry authorities
- GMP certification
- USP verification
- Public endorsements from fitness professionals unaffiliated with the manufacturer
Checking off one of more of the above items provides you with concrete criteria with which to evaluate a prospective supplement. When in doubt, ask around. Talk to your doctor.
Commence your supplement regimen with low doses to assess tolerance. Try several reputable manufacturers to gauge supplement efficacy. Discontinue use of a particular brand if it does nothing or makes you sick.