Updated April 15, 2025
Your skin is the largest organ in your body and needs high-quality nutritional support for optimal functioning and health. Quercetin, a natural antioxidant, protects skin health from damage caused by pollution, UV radiation, and other environmental stressors.*
Get the answers to common queries about quercetin’s skin benefits, its potential health-promoting applications, its bioavailability and absorption challenges, and the best way to include quercetin 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 potent 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 as Quercetin-3-O-glycoside, primarily serves as a natural pigment in fruits, vegetables, and flowers. Key dietary sources of quercetin include:
- Apples
- Grapes
- Berries
- Cherries
- Citrus fruits
- Cruciferous vegetables
- Onions
- Kale
- Buckwheat
- Tomatoes
- Red wine
- Black tea
Quercetin concentrations can vary from one plant to another and even vary in different parts of the same plant. Onions, tea, and apples contain a significantly higher amount of quercetin.
Potential Applications of Quercetin
Flavonoids like quercetin are more powerful antioxidants than vitamins C and E. As a potent antioxidant that supports the body’s natural inflammatory responses, quercetin extends beneficial effects by inhibiting kinases, oxidative damage, and cell cycle growth, and supporting neuronal survival.* The following table lists potential applications for quercetin:
| System | Application |
Cardiovascular Health* |
|
Kidney Health* |
|
Immune Function* |
|
Gastrointestinal Health* |
|
Brain Health* |
What are Quercetin’s Skin Health Benefits?
Evidence suggests that the oxidative stress caused by reactive oxygen and nitrogen species plays a critical role in the development of various adverse skin disorders.1 The molecular characteristics of quercetin make it a potent scavenger of these reactive oxygen species (ROS) and reactive nitrogen species (RNS).* Quercetin’s ability to quench free radicals and support the skin’s cutaneous antioxidant defense system makes quercetin a preferred choice for extensive skin care applications.*
Quercetin helps maintain the body’s normal natural inflammatory responses by:
- Inhibiting the release of histamine.* Histamine is a critical compound for immune responses and is released by basophils and mast cells, that can lead to the skin feel itchy and appear red, swollen, and patchy.2
- Inhibiting the release of the proinflammatory cytokines and interleukin-4 (IL-4) and IL-13.* These signaling molecules are secreted by immune cells and trigger inflammatory responses.
The potential benefits quercetin offers for skin health can be condensed into two main functions: protection and restoration.*
| Quercetin’s Skin Benefits* | |
| Protection* | Restoration* |
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|
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Does Oral Ingestion of Quercetin Help?
Although quercetin can be obtained in the diet from various fruits and vegetables, it has poor natural absorption in the body.
| Studies show that only one percent of quercetin is absorbed naturally when it is ingested orally.5 |
Quercetin’s low natural absorption, extensive metabolism, and rapid elimination from the body contribute to its low bioavailability in nutritional supplements.
Factors Affecting Quercetin’s Absorption in the Body
Quercetin is primarily absorbed in the upper segment of the small intestine. Post-absorption, quercetin is metabolized in various organs, including the liver, small intestine, colon, and kidney, with the aid of biotransformation enzymes specific to the liver and small intestine. Finally, the kidney excretes quercetin and its metabolites in the urine.
Key factors affecting quercetin’s absorption in the body are:
- Poor aqueous solubility
- Instability in the 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)
Strategies to Enhance Quercetin’s Absorption
Conventional approaches used to enhance quercetin’s absorption include consuming the better-absorbed glycosylated form of quercetin, consuming sources with higher quercetin content, and consuming quercetin with dietary components.
- Differences in Glycosylation. The glycosyl group’s presence in quercetin’s molecular structure enhances its water solubility and increases 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 natural concentrations of quercetin than other sources.
- Co-Administration of Dietary Components. The intake of quercetin with dietary fat can increase its absorption, likely by micellarization in the small intestine.6
| 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, help overcome bioavailability-related issues in quercetin supplements. Nutritional supplements 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 metabolizing enzymes and other physiological conditions. Nanoparticles also enable a controlled release of quercetin molecules at the desired point in the intestinal tract.
The Most Bioavailable Form of Quercetin
The solubility of different forms of quercetin varies. Quercetin aglycones or glycosides in apples, tea, and red wine have lower solubility compared to quercetin glucosides from onions, which appear to have the highest absorption rate.
| Quercetin glucoside — the naturally occurring form of quercetin — displays an estimated absorption rate of 3%-17% per 100 mg of ingested quercetin.7 |
Why You Need A Quercetin Supplement
Because of its low water solubility, unformulated quercetin ranks low in terms of health-promoting benefits. Although dietary sources support the body with lower concentrations of quercetin, consuming a higher concentration can require taking quercetin in nutritional supplement form. 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
Different Types of Quercetin Formulations
Various formulations of quercetin offer multiple delivery modes, including:
- Oral ingestion: Common types of oral nutritional supplements include tablet, capsule, and powder forms.
- Topical application: Liposomal formulations with lipid-based nanoparticles that encapsulate quercetin molecules 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.
FAQs: Frequently Asked Questions about Quercetin Supplements
Are there side effects to taking a quercetin supplement?
Quercetin intake as a nutritional 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 to consult a healthcare provider before including a quercetin nutritional supplement in your diet or taking one with a prescription medicine.
How do I determine the efficacy of a quercetin supplement formulation?
The desired efficacy of a quercetin supplement formulation lies in enhanced bioavailability and absorption of the active nutrient molecules. Tesseract Medical Research’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.*
Tesseract’s 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 achieve quercetin’s skin benefits.*
The power of Tesseract supplements lies in enhancing palatability, maximizing solubility, absorption and bioavailability, and micro-dosing multiple nutrients in a single, highly effective capsule. Shop products on our website and learn more about how they can support your immune health .*
References:
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
