Quercetin and immunity: the molecule allied to the immune system

quercetina e immunità

In short.

In detail we will talk about

Recent scientific research has uncovered a natural compound capable of supporting our immune system: quercetin.
This flavonoid offers numerous health benefits, but what are the actual benefits and how can we incorporate it into our diet?

Let’s find out together the correlation between quercetin and immunity and how quercetin can help in Covid prevention.

Quercetin: what it is and what it is used for

Quercetin is a flavonoid, a molecule found in many plant-based foods. It performs several functions within our body, including:

  • Antioxidant: protects cells from damage caused by free radicals
  • Anti-inflammatory: reduces inflammation and pain associated with various diseases
  • Immunomodulatory: modulates the activity of the immune system, promoting an appropriate response to infection

Quercetin is found in numerous foods, including apples, onions, green tea, and red wine. Due to its properties, this compound can offer several health benefits, including improving cardiovascular function, protecting brain cells, and preventing certain types of cancer.

But how does quercetin act in our body? Through what mechanism can it support the immune system and prevent the onset of disease? To answer these questions, it is necessary to know the history and characteristics of this molecule.


Quercetin was first discovered in 1936 by Hungarian biochemist Albert Szent-Györgyi, who identified it as part of a group of compounds called “vitamin P.” Subsequently, studies have shown that flavonoids, including quercetin, are not true vitamins but still have beneficial effects on human health.

Over the years, research on quercetin has revealed several properties of medical interest, including:

  • Antioxidant and anticancer effects
  • Anti-inflammatory and analgesic properties
  • Ability to modulate the immune response

Research continues to evolve and discover new potential uses for this flavonoid in medicine and nutrition and to highlight the importance of quercetin in the context of health and disease prevention.

Immune system

The immune system is a complex network of cells, tissues, and organs that protect our bodies from infection and disease. Quercetin acts in several ways to support and strengthen this system, including:

  • Modulation of immune cell activity: quercetin may influence the function of T lymphocytes and natural killer cells, which play a key role in defense against infection
  • Inhibition of inflammatory cytokine production: quercetin can reduce the production of molecules that promote inflammation, such as tumor necrosis factor-alpha (TNF-alpha) and interleukin-6 (IL-6)
  • Antiviral effects: quercetin may interfere with the replicative cycle of some viruses, limiting their spread within the body

These combined effects make quercetin an important ally for our immune system, helping to prevent and fight infections and maintain good health.


Covid, caused by the SARS-CoV-2 virus, highlighted the importance of an efficient immune system in fighting viral infections. Quercetin has attracted the interest of the scientific community for its potential role in the prevention and treatment of Covid due to its antiviral and immunomodulatory properties.

Studies to date have shown that quercetin can:

  • Inhibit virus entry into host cells by interfering with receptors used by the virus to enter cells
  • Limit viral replication by acting on different stages of the virus replicative cycle
  • Modulate the immune response, reducing the production of inflammatory cytokines and preventing the “cytokine storm” that can be harmful in severe cases of Covid

Although these results are promising, it is important to note that research on quercetin and Covid is still ongoing and that further studies are needed to confirm and further investigate these data.

Usage and dosage

Quercetin can be taken through the diet or in the form of dietary supplements. However, it is important to follow the recommendations of your doctor or nutritionist to determine the dosage best suited to your needs. Here are some general tips on the use and dosage of quercetin:

  • Diet: consuming foods rich in quercetin, such as apples, onions, green tea, and red wine, can help ensure adequate intake of this flavonoid
  • Supplements: quercetin supplements are available in several forms, including capsules, tablets and powders. The recommended dosage may vary depending on the product and individual needs, but is usually between 500 and 1,000 mg per day
  • Drug interactions: quercetin can interact with some drugs, such as anticoagulants and antiplatelet agents, so it is important to consult your doctor before taking quercetin supplements if you have ongoing drug therapies

It is crucial to remember that quercetin is not a substitute for a balanced diet and healthy lifestyle, but it can be a valuable support for the immune system and disease prevention.

Let us now see what are some of the most common questions on this topic:


1. What are the main foods rich in quercetin?
Apples, onions, green tea, red wine, berries, kale and broccoli are some of the foods richest in quercetin.
2. Can quercetin cause side effects?
Quercetin is generally well tolerated, but in some cases it can cause side effects such as headache, nausea, and gastrointestinal upset. Consult your doctor before taking quercetin supplements.
3. Is quercetin useful in combating Covid?
Preliminary studies show promising results, but further research is needed to confirm the effectiveness of quercetin in the prevention and treatment of Covid.
4. Can I take quercetin during pregnancy or breastfeeding?
There are insufficient data on the use of quercetin during pregnancy and lactation. Consult your doctor before taking quercetin supplements during these periods.
5. Can quercetin interact with other drugs?
Yes, quercetin can interact with some drugs, such as anticoagulants and antiplatelet agents. Consult your doctor before taking quercetin supplements if you are taking other medications.

For more scientific insights, here is a (partial) bibliography of articles, studies and research:


  1. Boots, A. W., Haenen, G. R., & Bast, A. (2008). Health effects of quercetin: from antioxidant to nutraceutical. European Journal of Pharmacology, 585(2-3), 325-337. 
  2. Heinz, S. A., Henson, D. A., Austin, M. D., Jin, F., & Nieman, D. C. (2010). Quercetin supplementation and upper respiratory tract infection: A randomized community clinical trial. Pharmacological Research, 62(3), 237-242. 
  3. Colunga Biancatelli, R. M. L., Berrill, M., Marik, P. E. (2020). The antiviral properties of quercetin: A preliminary report. Preprints. 
  4. Derosa, G., Maffioli, P., & D’Angelo, A. (2020). Quercetin: A potential adjuvant in the prevention and therapy of COVID-19. Mini Reviews in Medicinal Chemistry, 20(22), 2213-2223. https://pubmed.ncbi.nlm.nih.gov/32720534/
  5. Khanna, K., & Kohli, S. K. (2021). Quercetin, a lead compound against type 2 diabetes ameliorates glucose uptake via AMPK pathway in skeletal muscle cell line. Frontiers in Pharmacology, 12, 638018. 


In conclusion, quercetin is an ally molecule of the immune system due to its antioxidant, anti-inflammatory, and antiviral properties. Research continues to discover new potential uses for this flavonoid in medicine and nutrition. Consuming quercetin-rich foods and using quercetin supplements can help support and strengthen the immune system, preventing and fighting infections and diseases, including Covid.


If you are interested in purchasing Ribovita QUERCETIN, visit the Salusfy online store.

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