Quercetin’s molecular structure

Quercetin Supplement Benefits

Are you aware of the health benefits of onions? Although onions are commonly used for flavoring, onions are a nutrient-dense superfood that contains quercetin, an antioxidant that promotes multiple health functions. So, what are quercetin supplement benefits? Should you consider including a quercetin supplement in your diet? 

Get answers to common questions about the benefits of quercetin supplements, including how quercetin supplements support health and the best way to include one in your diet. Use the links below to jump ahead to a topic of interest.

What Is Quercetin and Where Is It Found?

Quercetin is a flavonoid (a type of plant compound known for its antioxidant properties) found in various fruits and vegetables. Some of the richest sources include onions, capers, apples, berries, grapes, green leafy vegetables, and honey, as well as green and black tea. Onions contain a high amount of quercetin, with the outer layers containing the highest concentration.1 The unique biological properties of quercetin are linked to maintaining the body’s natural inflammatory response and limiting oxidative stress to promote overall health.*

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Potential Applications of Quercetin

Quercetin displays antioxidant and immunomodulatory properties2, in addition to possessing mast cell stabilizing3 and gastrointestinal cytoprotective activities4. Quercetin supplement benefits have been attributed to these two primary properties of the flavonoid:

  • Antioxidative properties of quercetin: Quercetin’s antioxidant properties enable it to regulate the enzyme-mediated and non-enzyme-dependent antioxidant defense system.* It also regulates cell signaling pathways triggered by reactive oxygen species (ROS) to promote the antioxidant defense system.5 
  • Immunomodulatory properties of quercetin: Quercetin supports a healthy immune response by modulating immune cells such as dendritic cells, T-helper cells, neutrophils, and microglia, making it a promising therapeutic botanical compound for various immune-related conditions.6,7,8,9

The following table summarizes the potential beneficial applications of quercetin. 

System

Beneficial Applications

Cardiovascular Health*

  • Quercetin inhibits the oxidation of low-density lipoproteins (LDL) and helps maintain normal blood pressure levels and healthy arteries.10
  • Learn more about quercetin for heart health support.*

Immune Health*

Renal Health*

  • Quercetin’s antioxidant properties support the reduction of oxidative stress on the kidneys,    promoting healthy kidney function.12
  • Learn more about quercetin for kidney health.*

Skin Health*

  • Quercetin helps maintain healthy skin integrity, which can be compromised by  UV radiation and toxic chemicals. In addition, quercetin plays a role in skin restoration by supporting skin hydration through its moisturizing effects.13
  • Learn more about quercetin skin benefits.*

Gastrointestinal Health*

  • Quercetin modulates gut microbial diversity in the gastrointestinal tract and helps maintain a normal inflammatory response in the gastrointestinal tract.14
  • Learn more about quercetin and gut health.*

How Does Quercetin Support Cardiovascular Health?

Oxidative stress is closely related to several cardiovascular disorders. The antioxidant and immunomodulatory properties of quercetin help mitigate oxidative stress and free radicals that can damage cardiovascular tissues.* The following table summarizes how quercetin benefits your heart.*

Quercetin and Heart Health*

Inhibiting Oxidation of Low-Density Lipoprotein (LDL)*

  • Quercetin inhibits oxidative damage to LDL by modulating cell signaling pathways, particularly the TLR-NF-κB pathway.15

Helping Maintain Normal Blood Pressure*

  • A meta-analysis found that quercetin supplementation (500 mg/ day or more) helped those with high blood pressure maintain healthier blood pressure levels.16

Inhibiting Expression of Adhesion Molecules*

  • Quercetin modulates the expression of specific cell surface proteins called adhesion molecules in human aortic endothelial cells to help maintain healthy arteries.17

Maintaining a Normal Inflammatory Response in Fat Cells and Support Healthy Glucose Metabolism*

  • Nutritional supplementation with quercetin has been found to help maintain a normal inflammatory response in fat cells as well as promote healthy glucose and insulin metabolism, supporting cardiovascular health.18

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How Does Quercetin Support Immune Function?

Quercetin alters several cell signaling pathways that down-regulate adverse allergic reactions and help maintain normal inflammatory responses.* The following table highlights how quercetin supports immune function and strengthens the body’s natural defense mechanisms.*

Quercetin and Immune Function
  • Supporting a healthy histamine response: Quercetin promotes the stabilization of mast cells, which release histamine — a signaling chemical involved in local allergic and immune response communication.19
  • Inhibiting proinflammatory cytokine production: Quercetin down-regulates cell signaling pathways (NF-κβ1 and Iκβ), inhibiting the production of proinflammatory cytokines and promoting a healthy inflammatory response.20
  • Inhibiting the production of leukotrienes: Quercetin is a potent inhibitor of leukotrienes — biochemical mediators produced in white blood cells that cause adverse immune responses, such as the tightening of airway muscles.21 
  • Enhancing Th1/Th2 balance: Quercetin promotes the balance between the two types of T-helper (Th) cells — Th1 and Th2 cells, promoting a healthy adaptive immune response.22
  • Down-regulation of antigen-specific IgE antibody formation: Quercetin inhibits the formation of Immunoglobulin E (IgE) antibodies that trigger antigen-specific allergic reactions.23

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Factors Affecting Quercetin Absorption in the Body

The upper segment of the small intestine absorbs the majority of quercetin.24 Post-absorption, quercetin undergoes metabolization in various organs, including the liver, small intestine, colon, and kidney. Quercetin and its metabolites are finally excreted through urine.

Historically, quercetin supplements have shown poor absorbability and, therefore, bioavailability.25 The key factors affecting quercetin’s absorption in the body are:

  • Low Aqueous Solubility (does not dissolve well in water)
  • Poor Permeability (does not easily get through the intestinal barrier)
  • Short Biological Half-Life (quick elimination)
  • Instability in the stomach and intestine (easily broken down by stomach acid and other digestive molecules)

Extensive First-Pass Metabolism in the Liver (quicker biotransformation into other molecules)

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Quercetin Supplement Formulations

Quercetin accounts for 75 percent of a person’s daily estimated flavonoid intake, ranging from 50 – 800 mg/day.26 It is worth noting that quercetin intake through food sources mostly depends on consuming fruits, vegetables, and tea. So, even if you consume 10 – 100 mg of quercetin daily through different food sources, a supplement formulation can fill any nutritional gaps to help you realize quercetin’s benefits.

Commercially formulated quercetin supplements are available in oral (tablet, capsule, powder), intravenous (injectable formulations), intranasal (spray, nasal drops), and topical (ointments, gels, sprays) formats. A quercetin capsule or a coated tablet typically contains 400 – 600 mg of the active nutrient.

Novel Formulations

Novel formulations that have alternative delivery systems can overcome the absorbability and bioavailability challenges of quercetin supplements. The following benefits of nano-formulated molecules enhance the overall efficacy of quercetin supplement absorption.

  • Nanoformulated molecules achieve a larger surface area per molecule than their raw material counterparts.  
  • Such molecules can be customized for targeted delivery to the correct part of the intestine,  protecting them from early degradation and promoting optimal absorption.
  • Nanoformulated nutrient delivery also enables the controlled release of quercetin molecules at the desired point in the intestinal tract.

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FAQs: Frequently Asked Questions About Quercetin Supplement Benefits

Are there side effects to taking a quercetin supplement?

There is no significant reported toxicity or side effects of quercetin, and its intake as a nutritional supplement at one gram daily is generally considered safe. However, there is limited data on the prolonged usage of quercetin at levels at or above one gram daily for longer than 12 weeks.27 Ingesting too high amounts of quercetin can cause unwanted effects, such as depletion of intracellular glutathione content.28 

The complexity of potential interactions of prolonged quercetin intake indicates that quercetin use as a supplement should be taken after medical consultation.

Can I take a quercetin supplement with a prescription medicine?

Quercetin can interact with certain medications by reducing their absorption and effectiveness and raising the risk of side effects. Consult a health-care practitioner to know about potential contraindications before including a quercetin supplement in your diet or taking one with a prescription medication.

How do I determine the efficacy of a quercetin supplement?

The efficacy of a quercetin supplement lies in enhanced absorption and bioaccessibility of the active nutrient molecules. 

QuerciSorb QR® — innovative quercetin supplement formulations developed by Tesseract Medical Research as a quick-release or sustained-release format — incorporate a proprietary nanomolecular nutrient delivery technology (CyLoc® – DexKey®) to enhance the solubility and absorption of quercetin.* 

QuerciSorb Immuphore SR® contains quercetin along with additional immune-supporting ingredients, including vitamins C and D, and zinc, to promote healthy immune function.* 
Tesseract’s proprietary CyLoc® – DexKey® nutrient delivery nanotechnology further enhances the absorption of quercetin molecules at the desired point in the intestinal tract. The unprecedented absorption unlocks quercetin supplement benefits to support optimal cardiovascular health and immune function.*

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The power of Tesseract supplements lies in enhancing palatability, maximizing absorption and bioavailability, and micro-dosing of multiple nutrients in a single, highly effective capsule. Shop products on our website and learn more about how they can help support your cardiovascular health and immune function.*  

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Citations

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2Aghababaei F, Hadidi M. Pharmaceuticals (Basel). 2023;16(7):1020. Published 2023 Jul 18. doi:10.3390/ph16071020

3Ding Y, Che D, Li C, et al. Int Immunopharmacol. 2019;66:185-197. doi:10.1016/j.intimp.2018.11.025

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10. Kao TK, Ou YC, Raung SL, Lai CY, Liao SL, Chen CJ. Life Sci. 2010;86(9-10):315-321. doi:10.1016/j.lfs.2009.12.014

11. Mlcek, Jiri et al. Molecules (Basel, Switzerland) vol. 21,5 623. 12 May. 2016, doi:10.3390/molecules21050623

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13. Ha, Anh Thu et al. International journal of molecular sciences vol. 23,1 433. 31 Dec. 2021, doi:10.3390/ijms23010433

14. Sun, Lei et al. Molecules (Basel, Switzerland) vol. 27,10 3269. 19 May. 2022, doi:10.3390/molecules27103269

15. Bhaskar S, et al. Immunobiology vol. 216,3 (2011): 367-373. doi:10.1016/j.imbio.2010.07.011

16. Serban, Maria-Corina et al. Journal of the American Heart Association vol. 5,7 e002713. 12 Jul. 2016, doi:10.1161/JAHA.115.002713

17. Li C, et al. Redox Biology vol. 9 (2016): 104-113. doi:10.1016/j.redox.2016.06.006

18. Wang Y, et al. Nutrients vol. 16,8 1102. 9 Apr. 2024, doi:10.3390/nu16081102

19. Shaik Y, et al. Central-European Journal of Immunology vol. 43,4 (2018):476-481. doi:10.5114/ceji.2018.81347

20. Cheng S-C, et al. International Journal of Molecular Sciences vol. 20,12 2957. 17 Jun. 2019, doi:10.3390/ijms20122957

21. Loke WM, et al. Biochemical Pharmacology vol. 75,5 (2008):1045-53. doi:10.1016/j.bcp.2007.11.002

22. Ke, Xia et al. Autoimmunity vol. 56,1 (2023): 2189133. doi:10.1080/08916934.2023.2189133

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Al Czap, Founder | Tesseract

Al Czap has more than four decades of professional experience in preventative medicine. He founded Thorne Research in 1984 (sold in 2010) and he published Alternative Medicine Review for 17 years beginning in 1996. AMR was a highly acclaimed, peer-reviewed, and indexed medical journal. Al was the first to recognize the need for hypoallergenic ingredients and to devise methods of manufacture for and delivery of hypoallergenic products to underserved patient populations. His work has greatly impacted those with impaired immune and digestive systems and compromised health due to environmental exposures.

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