All, Anti Aging, Gut Health, Health and Wellbeing, Immune support, Pain and Inflammation, Stress

QUERCETIN: Everything you need to know

5 minute read

What’s all the fuss about Quercetin?

You’ve probably heard about the new fandangled supplement Quercetin! This nutrient has become VERY popular in the last few months due to its proposed immune enhancing and anti-viral benefits. But, like any health ‘trend’ we must question: Are these claims supported by research? Should we jump on the band wagon?

So, let’s take a look.

What is Quercetin? What are the benefits that have been backed by research? And can we get enough in our diet?

What is it?

Quercetin is a natural plant flavonoid found mainly in the skin and leaves of a variety of fruits, vegetables and plants, including onions, citrus, broccoli, apple, grapes, beans, and black and green tea. The amount of Quercetin in foods varies greatly – see table below. And this amount is also affected by others factors, such as farming practices, quality of harvest, processing etc.

Australian adults are estimated to consume approximately 8-16mg of Quercetin in their diet each day [i]. This is far lower than the therapeutic amount of Quercetin used in research to treat particuarly conditions. The therapeutic dose according to research is between 200mg-1500mg of Quercetin a day. So, we can see that it is difficult to guarantee a therapeutic dose via foods when our goal is the treatment of a condition.

Note: Above table shows the estimated amounts of Quercetin per average serve in several high Quercetin containing foods and drinks in Australia [i] 

What does the research say?

Quercetin’s popularity is due to the numerous effects on the immune system which have been very widely researched. It is recently gained much attention and popularity due to its anti-viral and anti inflammatory effects.

  1. Anti-allergy & asthma: Quercetin is a natural antihistamine that has been shown to reduce allergies, rhinitis and hayfever symptoms. Which include sneezing, runny nose, itchy eyes, wheezing, coughing, eczema, skin rashes, diarrhoea, reflux, glassiness, irritability and hives. It works by reducing the activation of your Mast cells which are responsible for histamine release.  Histamine is a key driver of all those above allergy/hayfever symptoms
  2. Anti-inflammatory: Quercetin has been shown to reduce inflammatory proteins in the body (e.g. cytokines, chemokines and leukotrienes). A recent study on 50 women with rheumatoid arthritis found that 8 weeks of supplementing Quercetin at 500mg/day significantly reduced inflammatory markers and reduced symptoms such as joint pain [v]
  3. Anti-viral: Research shows that Quercetin can reduce the replication of viruses and act as a preventative against viruses, including respiratory viruses, influenza, parainfluenza and rhinovirus [ii][iii]
  4. Zinc ionophore activity: Quercetin is a natural Zinc ionophore- meaning it helps zinc to enter our cells which has been shown to significantly enhance our immune system [iv]
  5. Food allergies, intolerances and sensitivities: Shown to reduce GIT issues related to food intolerances and allergies (gut pain, bloating, cramps, diarrhoea, constipation etc.)
  6. Antioxidant: Works by cleaning up free radicals (i.e. broken down cells and wastes) in the body that can damage DNA and cells.
  7. Potential anti-cancer: Further research is required to understand Quercetin’s potential effect in more depth; however the early animal studies show promising anti-cancer effects[vi]

Other benefits of Quercetin include its ability to help calm the nervous system, reduces stress, reduce headaches, reduce insomnia, increase energy levels, support a healthy cardiovascular system and general support vitality and wellness.

The bottom line

As we can see from the research, Quercetin has countless benefits to our health and wellbeing. Quercetin supplements have been used for decades by health practitioners as an effective natural therapy instead of, or alongside, conventional medical treatments with great outcomes (and without the nasty side effects that can come with pharmaceutical anti histamines and SSRIs etc.).

To maintain and optimise general wellbeing, it is recommended to include a variety of Quercetin-rich wholefoods as a part of a balanced diet. You can increase the amount of Quercetin in your diet by;

  • Adding more vegetables to your main meals- aim for approximately ½ of your main meal to be made up of a variety of vegetables
  • Enjoy up to 2 pieces of fruit a day, onions, citrus, broccoli, red wine, and lots of tea
  • If you are going to drink alcohol, opt for a sulphite-free organic red wine, and drink in moderation (no more than 4 drinks on one occasion and at least 2 alcohol free nights a week)

Disclaimer: This site should not be used to diagnose, treat, prevent or cure any disease or condition. Consult your medical practitioner before using any dietary supplement. Do not use if pregnant or nursing (breastfeeding).


[i] Somerset, Shawn & Johannot, Lidwine. (2008). Dietary Flavonoid Sources in Australian Adults. Nutrition and cancer. 60. 442-9. 10.1080/01635580802143836

[ii] Quercetin: A Promising Treatment for the Common Cold.

[iii] Quercetin as an Antiviral Agent Inhibits Influenza A Virus (IAV) Entry.

[iv] Read, S. A., Obeid, S., Ahlenstiel, C., & Ahlenstiel, G. (2019). The Role of Zinc in Antiviral Immunity. Advances in nutrition (Bethesda, Md.), 10(4), 696–710.

[v] Javadi F, Ahmadzadeh A, Eghtesadi S, Aryaeian N, Zabihiyeganeh M, Rahimi Foroushani A, et al. The effect of quercetin on inflammatory factors and clinical symptoms in women with rheumatoid arthritis: a double-blind, randomized controlled trial. J Am Coll Nutr. 2016 Oct 6;1-7.

[vi] Life or death: neuroprotective and anticancer effects of quercetin. Dajas F J Ethnopharmacol. 2012 Sep 28; 143(2):383-96.