Last updated: August 15, 2021

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Quercetin is a yellow natural pigment from the group of polyphenols and flavonoids, which is antioxidant and has positive effects on human health. Because of this protective and healing effect, quercetin is always in the focus of researchers and doctors and for this reason quercetin is also offered in concentrated form as a medicine to treat various diseases.

We present you our Quercetin test 2021. We will give you all the information you need about quercetin. You will learn how this substance and its health properties work and why this substance is so important for our body.




The most important facts

  • Quercetin is an important secondary plant substance that belongs to the flavonoid family. It is a yellow pigment found in a variety of plant seeds, but also in the skin of many edible foods such as onions.
  • Quercetin is an essential substance for our body that we cannot produce ourselves. As a food supplement, quercetin has good effects against high blood pressure, inflammation, viral infections, colds and is also used to treat cancer.
  • Therefore, we should consume various foods containing quercetin, such as broccoli, grapes, cherries, herbs, blackberries or blueberries, or take them as a food supplement. Quercetin can be found in various forms such as capsules or powder, and in combination with other substances such as vitamin C.

The Best Quercetin: Our Picks

Buying and evaluation criteria for Quercetin products

Now we will show you the criteria you should look for in order to choose the best quercetin product for you.

When choosing the right quercetin product for you, remember that you are not giving your body anything it doesn't really need. Therefore, always make sure that the quality is high and, if necessary, ask to see the manufacturer's certificates. We already pay attention to the high quality of the products in our presentation.

Composition

We can find quercetin in combination with other substances on the market, often with vitamin C, resveratrol, curcumin or bromelain. You should choose a micronutrient preparation of the highest quality.

High-quality preparations contain almost no allergens and are also free of unnecessary additives that often only aim to improve taste but provide no additional benefit to your health.

For example, the combined treatment of quercetin and vitamin C shows high protection against oxidative injury to human lymphocytes and neurovascular structures in the skin, preventing neuronal injury. In particular, this treatment protects brain cells from oxidative stress, which leads to Alzheimer's disease and other neurological conditions. (1)

On the other hand, the quercetin combination with other bioflavonoids such as resveratrol or curcumin also has beneficial synergistic effects.(2)

Taste

Before you choose a quercetin product, be sure to take a look at the label to discover what substances and ingredients the product contains.

In addition, a reputable supplier will provide easy-to-understand information about the amount of each active ingredient contained in the product.

It is important that we first know the percentage of quercetin in a product and then check that our product is not below or above the stated minimum or maximum dosages.

Quercetin capsules are mostly neutral in taste.

High-quality preparations have almost no allergens and do not contain many superfluous additives that only improve the taste but do not provide any additional benefits for your health. With quercetin preparations in capsule form, taste is a negligible factor.

However, some powders offer different tastes when you mix them into juices or water. Most quercetin powders are also vegan and gluten-free, although some products contain fructose. Therefore, always read the ingredients very carefully.

Form

We can find quercetin in different forms. Capsules are the most common format. This type is most convenient and best if, for example, you usually take the capsules outdoors. Capsules are also more convenient if you travel a lot for work or pleasure and want to have your supplements to hand.

Capsules and powdered quercetin usually have a shelf life of one to two years.

The quercetin powder should always be accompanied by a dosage spoon to make it easier to measure out the portion sizes.
You should shake a liquid medicine before consuming it. Mixing it into juice or diluting it with water may be recommended.

The products are fresh, so to keep them that way, please store them in the refrigerator after opening to protect the vitamins. This point is very important. Cold and darkness preserve vitamins longer than heat and light.

Quercetin capsules and powdered Quercetin usually have a shelf life of one to two years. Quercetin liposomals, i.e. liquid Quercetin mixtures, however, usually only have a shelf life of one to two months after opening.

Number of servings

You should always look at the label on each product to know what quercetin proportions the capsules or powders have and what active ingredients they contain. Normal dosages are between 250-500 mg per capsule for the capsules. A normal dosage for the powder sachet is between 800-1000 mg.

The usual can of capsules contains between 90 and 150 capsules per pack. However, in powder format, there are between 200-300 g in each sachet. In particular, you can often buy capsules in large stock packs.

This then also goes hand in hand with a (extrapolated) cheaper price. For quercetin liposomes, the bottle usually contains between 200-300 ml,and the recommended dosage per day is one serving of 5 millilitres each.

Guide: Frequently asked questions about Quercetin answered

In order to inform you comprehensively about the effectiveness of quercetin and to give you an understanding of the current state of science, we have summarised all the important information about the healing substance for you in the following sections.

What is quercetin and what is its function in our body?

Quercetin, a member of the flavonoid family, is one of the best-known antioxidants in food. It is ubiquitous in foods such as vegetables, fruit, tea and wine, as well as in countless dietary supplements, and has been shown to have beneficial effects on health. (3)

Quercetin has antioxidant properties.

Quercetin is a flavonoid with antioxidant properties. It is claimed that taking quercetin has many positive health effects, including protection against various diseases such as osteoporosis, lung cancer and cardiovascular disease.(4)

In particular, quercetin's ability to scavenge highly reactive species such as peroxynitrite and the hydroxyl radical is thought to be involved in these possible positive health effects.

What effects can we expect from quercetin?

The health benefits of quercetin lie in its strong anti-oxidant capacity with cell-protective properties. Like other flavonoids, quercetin lowers LDL cholesterol levels and blood pressure, and reduces the risk of cardiovascular disease. In addition to an anti-inflammatory effect quercetin also has apoptotic activity towards tumour tissues.

Effect on cancer

Cancer is a problem of global importance and the second leading cause of death worldwide.

Quercetin prevents the proliferation of various cancers (e.g. breast, lung, prostate, cervical, liver and colorectal) through different mechanisms of action, including cellular signalling, binding to cellular receptors and proteins, and inhibiting enzymes responsible for the activation of carcinogens.(5)

Cancer cells reprogram their metabolism to support their uncontrolled expansion by increasing biomass at the expense of their energy needs.

The anticancer effects of quercetin include its ability to promote loss of cell viability, apoptosis and autophagy through modulation of the PI3K / Akt / mTOR, Wnt / β-catenin and MAPK / ERK1 / 2 pathways. (6)

Effect in neurodegenerative diseases

Ageing is the main risk factor for neurodegenerative diseases such as Parkinson's or Alzheimer's disease. Oxidative stress and mitochondrial dysfunction are the main players in triggering neurodegeneration. Studies show that quercetin improves brain health and cognitive performance.

Quercetin can fight disease due to its antioxidant and anti-inflammatory properties. (7)

Antioxidants like quercetin can protect cells from damage caused by unstable molecules like free radicals. They reduce the risk of disease because they inhibit the oxidation of low-density lipoproteins and platelet aggregation and act as vasodilators in blood vessels.(8)

Effect arthritis

Rheumatoid arthritis (RA) is a prototypical autoimmune disease characterised mainly by joint inflammation and cartilage destruction. Neutrophils are actively involved in the initiation and progression of RA. Neutrophils express inflammatory mediators, including cytokines and chemokines.

Quercetin can lead to improvements in symptoms of rheumatism and arthritis. (Image source: 123rf / 9nong)

A study has shown that 500 milligrams per day of quercetin supplementation for 8 weeks led to significant improvements in clinical symptoms and decreased disease activity in women with rheumatoid arthritis. (9)

Other studies showed that quercetin inhibited inflammation in arthritis mice by infiltrating neutrophils and reduced plasma levels of inflammatory cytokines. These results suggest that quercetin may be an alternative agent for treating arthritis by inhibiting neutrophil activity.(10)

Anti-inflammatory effect

The anti-inflammatory property of quercetin may positively influence vascular health and protect the cardiovascular system from further damage.

According to a 2007 study in which a group of people were given 730 mg of quercetin over a period of just under a month, a reduction in systolic and diastolic blood pressure was demonstrated in hypertensive patients. These data have shown that quercetin supplementation lowers blood pressure in hypertensive subjects.(11)

What is the appropriate dosage of quercetin?

Quercetin is one of the major bioflavonoids found in more than twenty plants. It is known for its anti-inflammatory, antihypertensive, vasodilator, anti-obesity, antihypercholesterolemic and antiatherosclerotic activities.(12)

Most clinical trials use quercetin at 500 to 1000 mg per day taken throughout the day. (13)

As a supplement, 2 weeks of quercetin 50 mg achieved a 178% increase in serum levels, while quercetin 100 mg a had a 359% increase in serum levels, and quercetin 500 mg had a 570% increase in serum levels, albeit with wide individual variation. (14)

It is estimated that the average person consumes 10 to 100 mg of quercetin daily through various food sources. (Image source: unsplash / Benedikt Geyer)

Check the recommended dose before you take quercetin to find the right product for you. If you take higher doses over a longer period of time, you may experience side effects.

What types of quercetin are there?

There are different Quercetin product on the market. Before you decide on a product, you should learn about the different types. We have compared the different Quercetin products to make your choice easy.

Type Features
Quercetin capsules easy to swallow with some liquid
highly concentrated quercetin, high dosage of active ingredients possible, Prices for quercetin capsules are higher, They usually have a shelf life of two years
Quercetin powder Adjust dosages individually, mix with water or shakes, Also vegan- and gluten-free, They usually have a shelf life of one year.
Quercetin- Liposomales the uptake of quercetin is significantly increased store in the fridge well sealed for one to two months after opening.

The advantages and disadvantages of both variants will be explained in more detail in the next few paragraphs.

Quercetin capsules

Quercetin capsules are very easy to swallow with a little liquid. The quercetin contained in the capsules is usually very highly concentrated and has the advantage that a high dosage of the active ingredients is possible.

The capsule shells are often vegetable and allow vegans or vegetarians to take them. In addition, the capsules are very easy to carry when you travel, for example, and you can take the medication in any place.

You can buy quercetin as a dietary supplement online and in health food stores. It is available in various forms, including capsules and powders.(Image source: unsplash / Lore)

All you need is a little water. The price of quercetin capsules is higher than quercetin powder because of the higher production cost of the capsules.

Quercetin powder

If you have trouble swallowing larger capsules, then quercetin powders are the best choice for you. On the one hand, you can adjust the dosages individually and on the other hand, the powder can also be mixed into shakes without any problems.

Most quercetin powders are vegan and gluten-free, but some products contain fructose, which makes them unsuitable for people with fructose intolerance.

Liposomal quercetin

Liposomes are small vesicles that encapsulate a fat-soluble or water-soluble ingredient in the shell. Here, the active ingredient quercetin is protected from damage by the acidic stomach by a protective shell.

The liposomes can very easily fuse with the cell wall and deliver their encapsulated ingredients directly to the cell.

This can significantly increase the absorption of quercetin compared to conventional capsules. The bottle usually contains 200-300 ml and once opened for the first time, it must be kept tightly sealed in the refrigerator and used within 4-6 weeks.

What are the side effects of Quercentin?

The active ingredient quercetin is very healthy for our body and can be eaten in the form of food and will not harm our health. But as a chemically produced product, it can still be toxic in very high concentrations.

An overdose can produce side effects such as headaches or a tickling sensation in the arms and legs, and even damage to the kidneys. The wrong dose of quercetin can also cause mutations in the germ cells.

Therefore, it is important to follow the dosage instructions exactly when quercetin is given as a medicine for the treatment of diseases or for prevention.

In relation to other medicines, quercetin may interfere with the action of some antibiotics. So make sure you are well informed before taking it and consult your doctor or pharmacist if you wish.

Image source: photogonzo / 123rf

References (14)

1. Mlcek J, Jurikova T, Skrovankova S, Sochor J. Quercetin and Its Anti-Allergic Immune Response. Molecules. 2016;21(5):623. Published 2016 May 12. doi:10.3390/molecules21050623
Source

2. Nishtha SSrivastavaa1Rai Ajit KSrivastava Manor College of Veterinary Technology, Jenkintown, PA, United States bDrexel University School of Medicine, Philadelphia, PA, United States cIntegrated Pharma Solutions, Philadelphia, PA, United States,Curcumin and quercetin synergistically inhibit cancer cell proliferation in multiple cancer cells and modulate Wnt/β-catenin signaling and apoptotic pathways in A375 cells Received 4 May 2018, Revised 7 August 2018, Accepted 25 September 2018, Available online 28 September 2018.
Source

3. Boots AW, Haenen GR, Bast A. Health effects of quercetin: from antioxidant to nutraceutical. Eur J Pharmacol. 2008 May 13;585(2-3):325-37. doi: 10.1016/j.ejphar.2008.03.008. Epub 2008 Mar 18. PMID: 18417116.
Source

4. Anand David AV, Arulmoli R, Parasuraman S. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Source

5. Rauf A, Imran M, Khan IA, Ur-Rehman M, Gilani SA, Mehmood Z, Mubarak MS. Anticancer potential of quercetin: A comprehensive review. Phytother Res. 2018 Nov;32(11):2109-2130. doi: 10.1002/ptr.6155. Epub 2018 Jul 24. PMID: 30039547.
Source

6. Reyes-Farias M, Carrasco-Pozo C. The Anti-Cancer Effect of Quercetin: Molecular Implications in Cancer Metabolism. Int J Mol Sci. 2019;20(13):3177. Published 2019 Jun 28. doi:10.3390/ijms20133177
Source

7. Elumalai P, Lakshmi S. Role of Quercetin Benefits in Neurodegeneration. Adv Neurobiol. 2016;12:229-45. doi: 10.1007/978-3-319-28383-8_12. PMID: 27651256.
Source

8. Anand David AV, Arulmoli R, Parasuraman S. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Source

9. Javadi F, Ahmadzadeh A, Eghtesadi S, Aryaeian N, Zabihiyeganeh M, Rahimi Foroushani A, Jazayeri S. 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. 2017 Jan;36(1):9-15. doi: 10.1080/07315724.2016.1140093. Epub 2016 Oct 6. PMID: 27710596.
Source

10. Quercetin alleviates rheumatoid arthritis by inhibiting neutrophil inflammatory activities Author: Kai Yuan,Qingqing Zhu,Qingyi Lu,Haixu Jiang,Mengmeng Zhu,Xiaohong Li,Guangrui Huang,Anlong Xu Publication: The Journal of Nutritional Biochemistry Publisher: Elsevier Date: October 2020
Source

11. Edwards RL, Lyon T, Litwin SE, Rabovsky A, Symons JD, Jalili T. Quercetin reduces blood pressure in hypertensive subjects. J Nutr. 2007 Nov;137(11):2405-11. doi: 10.1093/jn/137.11.2405. PMID: 17951477.
Source

12. Anand David AV, Arulmoli R, Parasuraman S. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Source

13. Edwards RL, Lyon T, Litwin SE, Rabovsky A, Symons JD, Jalili T. Quercetin reduces blood pressure in hypertensive subjects. J Nutr. 2007 Nov;137(11):2405-11. doi: 10.1093/jn/137.11.2405. PMID: 17951477.
Source

14. 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.
Source

Why you can trust me?

Wissenschaftlicher Review
Mlcek J, Jurikova T, Skrovankova S, Sochor J. Quercetin and Its Anti-Allergic Immune Response. Molecules. 2016;21(5):623. Published 2016 May 12. doi:10.3390/molecules21050623
Go to source
Wissenschaftlicher Review
Nishtha SSrivastavaa1Rai Ajit KSrivastava Manor College of Veterinary Technology, Jenkintown, PA, United States bDrexel University School of Medicine, Philadelphia, PA, United States cIntegrated Pharma Solutions, Philadelphia, PA, United States,Curcumin and quercetin synergistically inhibit cancer cell proliferation in multiple cancer cells and modulate Wnt/β-catenin signaling and apoptotic pathways in A375 cells Received 4 May 2018, Revised 7 August 2018, Accepted 25 September 2018, Available online 28 September 2018.
Go to source
Wissenschaftlicher Review
Boots AW, Haenen GR, Bast A. Health effects of quercetin: from antioxidant to nutraceutical. Eur J Pharmacol. 2008 May 13;585(2-3):325-37. doi: 10.1016/j.ejphar.2008.03.008. Epub 2008 Mar 18. PMID: 18417116.
Go to source
Wissenschaftlicher Review
Anand David AV, Arulmoli R, Parasuraman S. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Go to source
Wissenschaftlicher Review
Rauf A, Imran M, Khan IA, Ur-Rehman M, Gilani SA, Mehmood Z, Mubarak MS. Anticancer potential of quercetin: A comprehensive review. Phytother Res. 2018 Nov;32(11):2109-2130. doi: 10.1002/ptr.6155. Epub 2018 Jul 24. PMID: 30039547.
Go to source
Wissenschaftlicher Review
Reyes-Farias M, Carrasco-Pozo C. The Anti-Cancer Effect of Quercetin: Molecular Implications in Cancer Metabolism. Int J Mol Sci. 2019;20(13):3177. Published 2019 Jun 28. doi:10.3390/ijms20133177
Go to source
Wissenschaftlicher Review
Elumalai P, Lakshmi S. Role of Quercetin Benefits in Neurodegeneration. Adv Neurobiol. 2016;12:229-45. doi: 10.1007/978-3-319-28383-8_12. PMID: 27651256.
Go to source
Wissenschaftlicher Review
Anand David AV, Arulmoli R, Parasuraman S. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Go to source
Wissenschaftlicher Review
Javadi F, Ahmadzadeh A, Eghtesadi S, Aryaeian N, Zabihiyeganeh M, Rahimi Foroushani A, Jazayeri S. 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. 2017 Jan;36(1):9-15. doi: 10.1080/07315724.2016.1140093. Epub 2016 Oct 6. PMID: 27710596.
Go to source
Wissenschaftlicher Review
Quercetin alleviates rheumatoid arthritis by inhibiting neutrophil inflammatory activities Author: Kai Yuan,Qingqing Zhu,Qingyi Lu,Haixu Jiang,Mengmeng Zhu,Xiaohong Li,Guangrui Huang,Anlong Xu Publication: The Journal of Nutritional Biochemistry Publisher: Elsevier Date: October 2020
Go to source
Wissenschaftlicher Review
Edwards RL, Lyon T, Litwin SE, Rabovsky A, Symons JD, Jalili T. Quercetin reduces blood pressure in hypertensive subjects. J Nutr. 2007 Nov;137(11):2405-11. doi: 10.1093/jn/137.11.2405. PMID: 17951477.
Go to source
Wissenschaftlicher Review
Anand David AV, Arulmoli R, Parasuraman S. Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid. Pharmacogn Rev. 2016;10(20):84-89. doi:10.4103/0973-7847.194044
Go to source
Wissenschaftlicher Review
Edwards RL, Lyon T, Litwin SE, Rabovsky A, Symons JD, Jalili T. Quercetin reduces blood pressure in hypertensive subjects. J Nutr. 2007 Nov;137(11):2405-11. doi: 10.1093/jn/137.11.2405. PMID: 17951477.
Go to source
Wissenschaftlicher Review
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.
Go to source
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