Understanding Quercetin’s Skin Benefits 

Your skin is the largest organ in your body and needs high-quality nutritional support for optimal functioning. Quercetin, a natural antioxidant, helps protect your skin’s health from damage caused by pollution, UV radiation, and other environmental stressors.* 

Get the answers to common queries about this wondrous molecule, including how it offers therapeutic benefits for your skin and the best way to include it in your diet. Use the links below to jump ahead to different topics on the page.

What Is Quercetin and Where Is It Found?

Quercetin is a naturally occurring phytochemical, or flavonoid compound, found in fruits and vegetables. Quercetin and its derivatives have antioxidant properties that help regulate the body’s natural inflammatory response, translating to powerful positive bioactive effects on cell cycle progression and cellular signaling pathways.* 

Quercetin, mainly Quercetin-3-O-glycoside, primarily serves as a pigment in fruits, vegetables, and flowers. Some key dietary sources of quercetin include apples, grapes, berries, cherries, citrus fruits, cruciferous vegetables, onion, kale, buckwheat, tomatoes, red wine, and black tea. It is worth noting that quercetin concentrations can vary from one plant to another or even in different parts of the same plant. Onions, tea, and apples contain significantly higher amounts of quercetin.

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Potential Therapeutic Applications of Quercetin 

Flavonoids like quercetin are considered more powerful antioxidants than vitamins C and E. As an antioxidant that supports the body’s natural inflammatory responses, quercetin extends therapeutic effects mainly by inhibiting kinases, oxidative damage, and cell cycle growth and supporting neuronal survival.* The following table lists some potential therapeutic applications for quercetin in the human body.*

System	Therapeutic Applications
Cardiovascular Health*	Quercetin for Heart Health Support Quercetin vs CoQ10: Which to Choose
Kidney Health*	Quercetin for Kidney Health Support: Benefits
Immune Function*	Exploring Alternative Allergy Therapy: The Potential Benefits of Quercetin
Gastrointestinal Health*	Does Quercetin Help Leaky Gut? Understanding The Science Behind An Innovative Treatment
Brain Health*	Research Supports Using A Quercetin Supplement to Benefit Alzheimer’s Disease Symptoms Does Quercetin Affect Sleep: FAQs Nutritional Support Supplements for Parkinson’s Disease: Considering Quercetin

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How Does Quercetin Support Skin Health? 

Evidence¹ suggests that oxidative stress caused by reactive oxygen and nitrogen plays a critical role in the development of various skin disorders. The molecular features of quercetin make it a potent scavenger of reactive oxygen species (ROS) and reactive nitrogen species (RNS).* Quercetin’s ability to quench free radicals and support the cutaneous antioxidant defense system makes it a preferred choice for extensive skin care and therapeutic applications.*

In helping to maintain the body’s normal natural inflammatory responses, quercetin has been found² to inhibit the release of histamine—a critical compound for immune responses—from basophils and mast cells.* Quercetin can also inhibit the release of the proinflammatory cytokines and interleukin-4 (IL-4) and IL-13, the signaling molecules secreted by immune cells to trigger inflammatory responses.*

The potential benefits quercetin offers for skin health can be condensed into two main functions: protection and restoration.*   

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Does Oral Ingestion of Quercetin Help?

Although quercetin can be obtained in the diet from various fruits and vegetables, it is poorly absorbed in the body. 

Studies⁵ show that only one percent of quercetin is absorbed when it is ingested orally.   

Quercetin’s low absorption, extensive metabolism, and rapid elimination from the body contribute to its low bioavailability from nutritional supplements.   

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Factors Affecting Quercetin Absorption in the Body

Quercetin is primarily absorbed in the upper segment of the small intestine. Post-absorption, the flavonoid is metabolized in various organs, including the liver, small intestine, colon, and kidney, with the help of biotransformation enzymes specific to the liver and small intestine. Finally, the kidney excretes quercetin and its metabolites in the urine.

The key factors affecting quercetin’s absorption in the body are:

• Poor Aqueous Solubility
• Instability in Physiological Medium (Stomach and Intestine)
• Poor Permeability
• Short Biological Half-Life (resulting in rapid degradation)
• Extensive First-Pass Metabolism in the Liver (resulting in extensive biotransformation)

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Strategies to Enhance the Absorption of Quercetin

Some conventional approaches have been to enhance quercetin absorption, such as intake of the better-absorbed glycosylated form of quercetin, consumption of sources with higher quercetin content, or consuming quercetin with dietary components.   

• Differences in Glycosylation. The glycosyl group’s presence in quercetin’s molecular structure impacts its water solubility and influences the absorption of quercetin glycosides. For example, the body absorbs quercetin glucosides found in onions or shallots more readily than its rutinosides — the major quercetin glycoside in tea. 

• Food Matrix of Quercetin Consumption. Certain foods, like onions, asparagus, and berries have relatively higher concentrations of quercetin compared to other sources.  

• Co-Administration of Dietary Components. The intake of quercetin with dietary fat has been found⁶ to increase its absorption, likely by micellarization in the small intestine.  

The ideal strategy for enhancing quercetin’s bioavailability is to protect its integrity in the upper gastrointestinal tract and release it in the colon with prolonged sustained release.

Novel Formulations

Alternative delivery systems, including nanoformulations, can help overcome bioavailability-related issues in quercetin supplements. Nutraceuticals formulated at the nanoparticle level achieve a larger surface area compared to their typical raw material counterparts.  They can be customized for targeted delivery of quercetin molecules while protecting their integrity against enzymes and other physiological conditions. Nanoparticles also enable a controlled release of quercetin molecules at the desired point in the intestinal tract.  

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The Most Bioavailable Form of Quercetin

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It is worth noting that the solubility of different forms of quercetin varies. Quercetin aglycones or glycosides in apples, tea, or red wine have lower solubility compared to quercetin glucoside from onions, which appear to have the highest absorption rate.

Quercetin glucoside — the naturally occurring form of quercetin — displays⁷ an estimated absorption rate of 3%-17% per 100 mg of ingested quercetin.

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Why Do You Need A Quercetin Supplement?

With its low water solubility, unformulated quercetin ranks low in terms of therapeutic benefits. Although dietary sources do support your body with lower concentrations of quercetin, consuming a higher concentration can require a nutritional supplement. Strategies like structural transformation, absorption enhancers, carrier complexes, and nanotechnology help develop highly bioavailable quercetin supplement formulations for benefits including:

• Better absorption 
• Minimized frequency and amount of quercetin intake

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Different Types of Quercetin Supplements

Various forms of quercetin supplements offer multiple delivery modes, including:

• Oral ingestion: The most common types of oral nutritional supplements are available in tablet, capsule, and powder forms. 

• Topical application: A liposomal formulation with lipid-based nanoparticles that encapsulate quercetin molecules can enhance the topical delivery of quercetin in the form of ointments, gels, and sprays.  

• Intravenous injection: Injectable formulations of water-soluble quercetin are used to address a wide range of pathological conditions. 

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FAQs: Frequently Asked Questions About Oral Quercetin Supplements 

Are there side effects to taking a quercetin supplement?

Quercetin intake as a dietary supplement at one gram daily³ is considered safe; adverse side effects from quercetin supplementation have rarely been reported. However, the clinical results of long-term quercetin use at levels at or above one gram daily for longer than 12 weeks are yet to be determined.

Can I take a quercetin supplement with a prescription medicine?

It is always recommended that you consult with your health-care provider before including a quercetin nutritional supplement in your diet or taking one along with a prescription medicine.  

How do I determine the efficacy of a quercetin supplement formulation?

The efficacy of a quercetin supplement formulation lies in enhanced bioavailability and absorption of the active nutrient molecules. Tesseract’s QuerciSorb Immuphore SR^®, an innovative quercetin supplement complex, contains four ingredients — quercetin, zinc, vitamin C, and vitamin D — to support the immune system’s optimal functioning, which includes healthy skin.*

The proprietary CyLoc^® – DexKey^® technology is a revolutionary nanomolecular nutrient delivery system that enhances the absorption of quercetin molecules by releasing them at the desired point in the intestinal tract. The unprecedented levels of absorption and bioavailability in each quercetin molecule enable micro-dosing of this formulation to support immune function all day long.*

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Citations:

¹Byamba D, et al. Annals of Dermatology vol. 22,3 (2010): 269-278. doi:10.5021/ad.2010.22.3.269

²Weng Z, et al. PloS One vol. 7,3 (2012): e33805. doi:10.1371/journal.pone.0033805

³Shin, EJ, et al. International Journal of Molecular Sciences vol. 20,21 5262. 23 Oct. 2019, doi:10.3390/ijms20215262

⁴Maramaldi , et al. Clinical, Cosmetic and Investigational Dermatology vol. 9 55-62. 26 Feb. 2016, doi:10.2147/CCID.S98890

⁵Gugler R, et al. European Journal of Clinical Pharmacology vol. 9,2-3 (1975): 229-234. doi:10.1007/BF00614022

⁶Guo Y, et al. Molecular Nutrition & Food Research vol. 57,5 (2013): 896-905. doi:10.1002/mnfr.201200619

⁷Li Y, et al. Nutrients vol. 8,3 167. 15 Mar. 2016, doi:10.3390/nu8030167