Quercetin is a natural plant pigment found in many foods common in the diet, including fruits, vegetables, and grains. It’s one of the most abundant antioxidants in the diet. Antioxidants help protect you from molecules known as free radicals, which can cause damage to the cells and lead to chronic illnesses. Eating a diet rich in antioxidants helps prevent this damage, and may reduce inflammation, allergy symptoms, and blood pressure.

You probably get enough quercetin through your diet; it is commonly found in foods like onions, apples, berries, and citrus fruits, and in coffee, tea, and red wine. Quercetin can also be added as a dietary supplement and is often offered in capsule form.

Recently, researchers have been investigating the possibility of using quercetin supplements as a treatment for patients with COVID-19 infections.[1] It’s important to remember that these findings are preliminary and clinical trials must be done before determining whether quercetin is an effective treatment.

While there’s no evidence that quercetin can prevent or cure COVID-19, it is known to have antiviral and anti-inflammatory properties, which may translate to fighting the coronavirus.  Early research shows that quercetin might be effective in treating COVID-19 cases by preventing it from replicating in the body.

As the COVID-19 vaccine rollout continues, it’s worth investigating the role of antioxidants in your wellness routine.

Does quercetin protect against COVID-19?

There is not enough evidence to show that quercetin can prevent or treat COVID-19. However, recent studies have shown that it may prevent COVID-19 from replicating within the body, helping to fight infection and lessen symptoms.

In a recent study, researchers looked at plant-based chemicals to see if treatments for COVID-19 might be found in drugs we’re already using.  Quercetin was identified as a top contender, and it has the potential to significantly interfere with a SARS-CoV-2 infection. It may bind to COVID-19 cells, preventing them from infecting host cells and spreading the virus further throughout the body.

Clinical trials must be done before there is evidence that a patient could receive quercetin as a treatment for a COVID-19 infection.

How much quercetin should I take?

In general, you probably get the right amount of quercetin from the food you eat, especially if you have plant-based foods into your diets. However, evidence shows that quercetin supplements can help with inflammation, allergy symptoms, immune response, and more.

Typical dosages range from 500–1,000 mg per day.[2] Evidence suggests that it is safe to take as a supplement, though taking more than the highest recommended dosage may lead to side effects like headaches or stomach aches.

You should check with your doctor before you introduce quercetin into your wellness routine; it can interact with other medications and produce side effects. Because bodies don’t easily absorb quercetin, supplements are often compounded with other ingredients to help absorption.

Can I take any vitamins or supplements to prevent COVID-19?

There is not enough evidence to claim that vitamins or supplements can prevent or cure COVID-19. However, studies have shown that certain vitamins and supplements help support your immune system and may reduce the severity of COVID-19 symptoms. Vitamin D, magnesium and vitamin B might be especially useful.

Vitamins and supplements shouldn’t replace wearing masks and social distancing for COVID-19 prevention. However, they could be worthwhile additions to a wellness routine and may remain beneficial once the public health crisis passes.

A key takeaway: try to make sure you’re eating a nutritious, plant-rich diet and consider introducing supplements into your health care routine if you are concerned about nutrient levels.

If you’re interested in adding quercetin to your routine, visit our antioxidant supplements page to explore options from trusted brands and find the right product for your needs.


[1] Derosa G, Maffioli P, D’Angelo A, Di Pierro F. A role for quercetin in coronavirus disease 2019 (COVID-19). Phytotherapy Research. 2020;1–7. https://doi. org/10.1002/ptr.6887

[2] Jin F, Nieman DC, Shanely RA, Knab AM, Austin MD, Sha W. The variable plasma quercetin response to 12-week quercetin supplementation in humans. Eur J Clin Nutr. 2010 Jul;64(7):692-7. doi: 10.1038/ejcn.2010.91. Epub 2010 Jun 2. PMID: 20517329.