Quercetin: The Queen of Antioxidant Supplements

Quercetin: The Queen of Antioxidant Supplements
Quick: name an antioxidant, any free-radical-killing antioxidant. If you’re like 9 out of 10 people, you’re probably thinking vitamin C. While vitamin C should indeed be a part of your wintertime immune-supporting arsenal—especially these 3 fruits—there’s one supplement that might even outshine vitamin C in antioxidant capacity: quercetin. You’ve heard of quercetin. Now it’s time to learn about this supplement that benefits health in many ways.

What is Quercetin?

It’s a natural source of a particular class of antioxidants called flavonoids that’s found in many fruits and vegetables. If you eat a lot of fruits and vegetables do you really need a quercetin supplement? Maybe, maybe not. The answer depends on the quality of the fruits and veggies you’re eating. Are they organic? And what about your lifestyle? How much exposure to air pollution, stress and pesticides do you undergo? If your immune system is bombarded on a daily basis—and whose isn’t—maybe you need an extra dose of free-radical fighting quercetin.

According to a 2016 article in Nutraceuticals, there’s reason to consider making room for quercetin in your supplement pantry. “There is growing evidence suggesting that quercetin has therapeutic potential for the prevention and treatment of different diseases, including cardiovascular disease, cancer, and neurodegenerative disease,” the co-authors write.

That’s an impressive list of potential benefits. But let's keep in mind that most studies have been performed in vitro (in cell lines) rather than in human clinical trials.

What is Quercetin Used For?


If you have allergies, quercetin may be as helpful as medication. How quercetin works is very similar to cromolyn, a preventive medication for allergies and asthma. The compound works by inhibiting the production of inflammatory enzymes (leukotrienes) that trigger asthma.

However, as the researchers note, don’t wait until symptoms kick in. “Quercetin must be used as a preventative—taken before allergen exposure,” the researchers suggest.

If you have springtime allergies, start taking quercetin a month or two before symptoms usually kick in. And if you experience allergy symptoms regardless of the season, the researchers recommend taking it year-round.

Blood Sugar Management

According to a study published by the American Chemical Society, research shows that quercetin “is a promising drug target for treating diabetes.” Scientists believe the “Q” supports blood sugar levels by increasing insulin sensitivity and by reducing insulin resistance.

In addition, the “Q” may improve stored carbohydrate (glycogen) metabolism and by stimulating pancreatic beta-cell proliferation. Beta cells are the manufacturing center of insulin, the hormone that controls blood sugar. 

Quercetin also helped battle high blood sugar levels by decreasing oxidative stress, the quality that it’s perhaps best known for.

Cardiovascular Health

In addition to being a magic pill for immune support, blood sugar management and  histamine/allergy prevention, quercetin has been shown to improve markers of heart health and circulation.

It does this by inhibiting an enzyme that narrows blood vessels (angiotensin). When blood vessels become too narrow, blood is unable to freely flow through the circulation. This leads to elevated blood pressure. Quercetin supports blood pressure better than the drug captopril, according to a study on rats.

Alzheimer’s Disease Prevention and Neurological Function

Because it’s an oxidative-stress-reducing powerhouse, quercetin is used in some formulas that may help prevent Alzheimer’s disease. It’s been shown to prevent the accumulation of amyloid-beta plaques, among other metabolic junk (for lack of a scientific explanation) that accumulates in the brain and causes neurodegenerative diseases.

Free-Radical Scavenging

Free radicals get a bum rap. Yes, they can cause disease. But if there were no free radicals, our immune system would have nothing to do and it would probably attack us out of boredom. Being healthy means that your immune system is able to fend off free radicals without excess oxidation causing premature cellular death.

However, when you’re bombarded by life’s myriad stressors, it may be a good idea to have quercetin on your side. That’s because it’s “an excellent antioxidant and probably the most potent scavenger of reactive oxygen species and reactive nitrogen species due to its two antioxidant pharmacophores for free-radical scavenging,” says this study. 

Best Foods With Quercetin

If your supplement drawer is full and you don’t feel like making room for quercetin, eat these foods that are rich in this health-supporting compound, according to Mt. Sinai:

  • Citrus fruits
  • Apples
  • Onions
  • Parsley
  • Sage
  • Tea
  • Olive oil
  • Grapes
  • Dark cherries
  • Dark berries 
  • Blueberries
  • Blackberries


Quercetin has received a lot of attention for its potential role in preventing or treating certain viruses, including THE ONE that has received global attention. However, there is no proof that quercetin can prevent or treat THE ONE. However, based on many research studies, it does seem to be a natural compound that supports health in several ways. 

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