Table of Contents

Quercetin: Benefits, Usage and Dosage

Takeaways

  • Quercetin is a natural antioxidant found in many fruits and vegetables
  • It may help reduce inflammation and allergy symptoms
  • Quercetin supports heart health and immune function
  • Supplements are available, but food sources are preferable
  • Typical dosages range from 500-1000 mg per day
  • Quercetin is generally safe but may interact with some medications

What is Quercetin?

Quercetin is a flavonoid, a type of plant-based compound known for its antioxidant capabilities.[1] This substance naturally occurs in numerous fruits, vegetables, and grains.[2] Specifically, quercetin is classified within the flavonol subgroup of flavonoids.[3]

Quercetin has attracted considerable interest due to its potential positive effects on health. Studies suggest it could be helpful for a variety of conditions, ranging from allergies to heart issues. The way quercetin functions in the body is primarily as an antioxidant, which combats damaging free radicals.[4]

Many people obtain quercetin through their daily food consumption. However, some individuals opt for supplements to achieve higher dosages. The body doesn’t absorb quercetin well on its own, which is why many supplements combine it with other substances to improve absorption.[5]

Natural Sources of Quercetin

Quercetin can be found in a wide variety of commonly eaten foods. It’s present in many fruits, vegetables, and even some drinks. Here are some notable sources:

Food Quercetin Content (mg per 100g)
Capers 234
Red onions 32
Kale 23
Blueberries 8
Red apples 4

Apples, especially the skin, are abundant in quercetin.[6] Red onions contain higher amounts compared to white or yellow onions.[7] Leafy greens such as kale and spinach are also good sources.[8] Berries, particularly blueberries and cranberries, are additional providers of this flavonoid.[9]

The amount of quercetin in food can vary considerably. Factors such as the growing environment, how ripe the produce is, and storage methods influence the levels. Generally speaking, the more vibrant the color of a fruit or vegetable, the more quercetin it contains.[10]

Cooking can cause a reduction in the amount of quercetin present in foods.[11] However, some cooking methods are better at preserving it than others. For instance, microwaving tends to retain more quercetin compared to boiling.[12]

Health Benefits of Quercetin

Antioxidant Properties

Quercetin is a potent antioxidant. It helps protect cells from the harm caused by unstable molecules known as free radicals.[13] These free radicals can damage cells, which can lead to various health problems.

The antioxidant actions of quercetin might be helpful in preventing chronic illnesses.[14] This includes conditions such as heart disease, cancer, and neurodegenerative disorders. By counteracting oxidative stress, quercetin aids in maintaining overall health and promoting longevity.

Research has demonstrated that quercetin can effectively neutralize a broad spectrum of free radicals.[15] In some instances, it has shown to be more effective than other antioxidants, like vitamin C.[16] This makes quercetin a valuable compound for preserving cellular health.

Anti-Inflammatory Action

Inflammation is a natural bodily response to injury or infection. However, when inflammation becomes chronic, it can contribute to various health issues. Quercetin has shown potential in reducing inflammation throughout the body.[17]

This flavonoid functions by inhibiting certain enzymes involved in inflammation.[18] It also lowers the production of substances in the body that promote inflammation. These actions could assist in managing conditions linked to long-term inflammation.

Studies suggest quercetin might provide support for inflammatory bowel diseases and could potentially alleviate the symptoms of rheumatoid arthritis.[19] While additional research is necessary, the anti-inflammatory qualities of quercetin are encouraging.

Allergy Relief

Quercetin’s potential to alleviate allergy symptoms is gaining attention. It works by stabilizing mast cells, which release histamine during allergic responses.[20] This can potentially reduce allergy symptoms like a runny nose and watery eyes.

This flavonoid also appears to reduce inflammation within the airways. This may be beneficial for individuals with asthma or other respiratory allergies.[21] Some research indicates that quercetin could be as effective as certain allergy medications.[22]

Although research is ongoing, many individuals use quercetin to manage their seasonal allergy symptoms. It’s often used in combination with other natural remedies, like vitamin C, for potentially enhanced effects. It is important to seek advice from a healthcare professional before using it for allergies.

Cardiovascular Health

Quercetin also demonstrates promise in supporting heart health. It might contribute to lowering blood pressure and decreasing the risk of heart disease.[23] These effects are likely a result of its antioxidant and anti-inflammatory characteristics.

Research suggests that quercetin may improve blood flow and reduce stiffness in the arteries.[24] Additionally, it could help lower levels of LDL, often referred to as “bad” cholesterol.[25] These combined effects could significantly reduce the risk of developing heart disease.

Studies indicate that quercetin could be particularly advantageous for people with elevated blood pressure. One specific study showed that it lowered systolic blood pressure by approximately 5 mm Hg and diastolic blood pressure by about 2.6 mm Hg.[26]

Immune System Support

Quercetin may enhance immune system function in several ways. It possesses antiviral characteristics and may help the body combat infections.[27] This flavonoid also supports the production and activity of immune cells.[28]

Research has shown that quercetin can inhibit the replication of various viruses.[29] These include influenza viruses and the herpes simplex virus.[30] It may also help in reducing the severity and duration of upper respiratory infections.[31]

The immune-boosting effects of quercetin are especially noteworthy during cold and flu season. Some individuals use quercetin supplements to help prevent illness. However, additional research is needed to fully grasp its impact on immune health.

Quercetin Supplements

Forms and Formulations

Quercetin supplements are available in a variety of forms. The most common include capsules and tablets. Certain products combine quercetin with other substances to improve its absorption. Here are some commonly used forms:

  • Pure quercetin capsules
  • Quercetin with bromelain (an enzyme from pineapple)
  • Quercetin with vitamin C
  • Quercetin dihydrate powder
  • Liposomal quercetin

Each form of quercetin has unique benefits. For example, combining quercetin with bromelain may enhance its absorption.[32] Liposomal formulations are designed to increase bioavailability.[33] Quercetin powder allows for flexible adjustments in dosage.

When selecting a supplement, consider factors like purity and whether it has undergone third-party testing. Look for products from well-known manufacturers.[34] Also, verify if the supplement contains any extra ingredients that might cause sensitivity.[35]

Dosage Recommendations

The dosage of quercetin can vary depending on its intended use. There isn’t a standard recommended dose. However, most studies use doses ranging from 500 to 1000 mg daily. Here’s a general guideline:

Purpose Typical Dosage Range
General health 500-1000 mg daily
Allergy relief 400-600 mg twice daily
Athletic performance 500 mg twice daily

It’s advisable to start with a smaller dose and increase it gradually, if needed. Some individuals take quercetin in divided doses throughout the day.[36] This might help in maintaining consistent levels within the body.

Remember that these are just general guidelines. The optimal dose may differ depending on personal factors like age, health status, and any other medications being taken. It’s always best to consult a healthcare provider before beginning any new supplement regimen.

Quercetin and Exercise Performance

Quercetin has attracted interest from athletes and fitness enthusiasts. Some research suggests it might enhance exercise performance and recovery.[37] These potential benefits are linked to its antioxidant and anti-inflammatory actions.

Studies have yielded varied results regarding quercetin’s effect on endurance. Some indicate it might improve VO2 max, which measures aerobic capacity.[38] Others show little to no effect. These differences could be attributed to factors such as the specific dosage used and individual responses.

Quercetin may help reduce inflammation and oxidative stress that can occur after exercise.[39] This could lead to faster recovery times between workouts and may also help in protecting against exercise-related muscle damage.

Here are some potential benefits of quercetin for athletes:

  1. Improved endurance
  2. Faster recovery
  3. Reduced muscle soreness
  4. Enhanced immune function during intense training
  5. Potential fat-burning effects

While these potential effects are promising, further research is required. The benefits might be more apparent in those who are untrained or new to intense exercise.[40] Elite athletes may not see as dramatic of a result.

If you are considering using quercetin to enhance exercise performance, begin with a moderate dose. Monitor your body’s response and make adjustments as necessary. As always, combine any supplement with a well-balanced diet and proper training for optimal results.

Quercetin Interactions and Side Effects

Drug Interactions

Quercetin can interact with several medications. These interactions can influence how the drugs function within your body. Here are some key interactions to keep in mind:

Quercetin could potentially interact with blood thinners like warfarin. It may increase the risk of bleeding.[41] If you are currently on blood thinners, it’s important to consult with your doctor before using quercetin supplements.

This flavonoid might also affect how the body processes certain antibiotics.[42] It could either increase or reduce their effectiveness. The same is true for some chemotherapy drugs.[43] Always inform your oncologist about any supplements you are taking.

Quercetin may interact with medications that are metabolized by the liver.[44] This includes many common drugs, and it could potentially amplify or diminish their effects. Discuss any potential interactions with your healthcare provider.

Possible Side Effects

Quercetin is generally considered safe when consumed through foods. However, high doses from supplements may cause side effects in some people. Commonly reported side effects include:

  • Headaches
  • Tingling sensations
  • Nausea
  • Upset stomach

Most side effects are mild and tend to resolve on their own.[45] They are more likely to occur with high doses or prolonged use. If you experience any persistent side effects, it may be best to reduce your dose or stop taking the supplement.

In rare cases, quercetin might cause more severe side effects. These could include kidney problems or allergic reactions.[46] If you notice any unusual symptoms, seek medical attention immediately.

Certain groups should be cautious with quercetin supplements:

  • Pregnant and breastfeeding women
  • People with kidney problems
  • Those with bleeding disorders

These groups should avoid using quercetin supplements unless advised by a healthcare provider. The long-term safety of its use has not been fully established. It is best to limit the use of quercetin supplements to short periods or only as directed by a healthcare professional.

Quercetin in Research

Quercetin has been the subject of numerous scientific studies. Researchers are investigating its potential advantages for various health conditions.[47] Although results are encouraging, further research is still necessary across many areas.

Current research is focusing on quercetin’s effects on:

  • Cancer prevention and treatment
  • Cardiovascular health
  • Neurodegenerative diseases
  • Metabolic disorders
  • Viral infections

Studies focusing on quercetin and cancer are particularly interesting. Some research indicates it might help in preventing certain forms of cancer.[48] It may also enhance the effectiveness of some chemotherapy drugs.[49] However, these findings are still preliminary and require additional investigation.

In the realm of cardiovascular research, quercetin shows potential in reducing the risk of heart disease. Studies have examined its influence on blood pressure, cholesterol levels, and inflammation. While results appear promising, more large-scale human trials are needed.

Researchers are also examining the neuroprotective characteristics of quercetin.[50] It may have potential in preventing or slowing the progression of neurodegenerative diseases. Studies relating to Alzheimer’s and Parkinson’s disease are ongoing.[51]

The antiviral properties of quercetin are another area of interest.[52] Recent studies have explored its potential against various viruses, including influenza and coronavirus. While initial findings are promising, more research is necessary to confirm these effects.[53]

Despite the encouraging results, there are limitations in current research:

  • Many studies are done in test tubes or animals
  • Human studies often have small sample sizes
  • Long-term effects of quercetin supplementation are not well-studied
  • Optimal dosages for specific conditions are not established

As research advances, we will gain a clearer understanding of the health advantages of quercetin. Currently, it is evident that this flavonoid has potential within numerous areas of health and well-being.

Incorporating Quercetin into Your Diet

Including foods that are rich in quercetin into your daily diet is a natural way to increase your intake. Many of these foods are already part of a healthy eating plan. Here are some tips to boost your quercetin consumption:

  1. Eat the rainbow: Colorful fruits and vegetables are often high in quercetin. Include a variety in your meals.

  2. Don’t peel apples: Much of the quercetin in apples is in the skin. Eat them whole for maximum benefit.

  3. Add onions to dishes: Red onions are particularly rich in quercetin. Use them in salads, sandwiches, and cooked dishes.

  4. Snack on berries: Blueberries, cranberries, and other berries are good quercetin sources.

  5. Drink green tea: This beverage contains quercetin and other beneficial compounds.

When preparing foods rich in quercetin, keep these tips in mind:

  • Raw foods generally retain more quercetin
  • If cooking, try steaming or microwaving instead of boiling
  • Combine quercetin-rich foods with sources of fat for better absorption

Remember, a well-rounded diet is essential for getting a wide range of nutrients. Don’t focus exclusively on foods rich in quercetin.[54] Instead, aim for a balanced diet with lots of fruits and vegetables.[55]

If you’re considering supplements, whole food sources are often the better choice.[56] They provide quercetin along with other beneficial nutrients. However, supplements may be useful in some cases. Always consult with a healthcare provider before beginning any supplement regimen.

FAQ: Common Questions About Quercetin

What is quercetin used for?
Quercetin is used for its antioxidant and anti-inflammatory properties. It may help with allergies, heart health, and immune support.

How much quercetin should I take daily?
Typical doses range from 500-1000 mg per day.[57] However, the optimal dose varies based on individual factors and health goals.

Can quercetin help with allergies?
Some studies suggest quercetin may help reduce allergy symptoms.[58] It works by stabilizing mast cells and reducing inflammation.[59]

Is quercetin safe during pregnancy?
The safety of quercetin supplements during pregnancy isn’t well established. Pregnant women should consult their doctor before using quercetin supplements.

How long does it take for quercetin to work?
The time frame can vary depending on the condition and individual. Some people notice effects within a few days, while others may take weeks.

Can quercetin interact with other supplements?
Yes, quercetin can interact with some supplements, especially those that affect blood clotting. Always consult a healthcare provider about potential interactions.

Conclusion

Quercetin is a compelling compound with diverse potential health benefits. From its antioxidant properties to its positive effects on heart health and allergies, quercetin has a lot to offer. While ongoing research continues, current evidence is quite promising.

Many individuals can benefit by increasing their quercetin intake through their diets. Consuming a variety of fruits and vegetables is a great approach to doing this. For those thinking about supplements, it’s important to approach them cautiously, with guidance from a healthcare professional.

Keep in mind that quercetin is just one part of a healthy lifestyle. It works most effectively when paired with a balanced diet, regular exercise, and other healthy behaviors. As with any supplement, it isn’t a magical fix but rather a tool that may support overall health and well-being.

As research progresses, we will discover more about the benefits and optimal uses of quercetin. At this time, it remains an intriguing compound that may support various aspects of health. Whether through diet or supplements, quercetin offers an appealing avenue for those wanting to improve their nutritional intake and support their well-being.

Fact Check
Claim: Quercetin is a flavonoid, a type of plant-based compound known for its antioxidant capabilities.
Fact check: True. Quercetin is a flavonoid with antioxidant properties.

Flavonoids are a class of plant compounds known for their antioxidant properties. Quercetin falls within this category.

Source: “Phytochemistry and pharmacology of natural prenylated flavonoids” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10101826/

Claim: This substance naturally occurs in numerous fruits, vegetables, and grains.
Fact check: True. Quercetin is found in various plant-based foods.

Quercetin is widely distributed in the plant kingdom and is found in many fruits, vegetables, and grains.

Source: “The Impact of Three-Month Quercetin Intake on Quality of Life and Anxiety in Patients With Type II Diabetes Mellitus: An Early Data Analysis From a Randomized Controlled Trial” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11091546/

Claim: Specifically, quercetin is classified within the flavonol subgroup of flavonoids.
Fact check: True. Quercetin is a flavonol.

Flavonoids are further divided into subgroups, and quercetin is indeed a flavonol, which is a specific type of flavonoid.

Source: “A Systematic Review: Quercetin—Secondary Metabolite of the Flavonol Class, with Multiple Health Benefits and Low Bioavailability” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11594109/

Claim: The way quercetin functions in the body is primarily as an antioxidant, which combats damaging free radicals.
Fact check: True. Quercetin’s primary function is as an antioxidant.

Quercetin acts as an antioxidant by neutralizing free radicals, which can cause cellular damage.

Source: “Recent Advances in Potential Health Benefits of Quercetin.” https://pubmed.ncbi.nlm.nih.gov/37513932/

Claim: The body doesn’t absorb quercetin well on its own, which is why many supplements combine it with other substances to improve absorption.
Fact check: True. Quercetin has low bioavailability and is often combined with other substances to improve absorption.

Quercetin has low bioavailability due to its poor water solubility and rapid metabolism. Combining it with other substances such as bromelain or using liposomal formulations can enhance its absorption.

Source: “A Systematic Review: Quercetin—Secondary Metabolite of the Flavonol Class, with Multiple Health Benefits and Low Bioavailability” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11594109/

Claim: Apples, especially the skin, are abundant in quercetin.
Fact check: True. Apple skin is a good source of quercetin.

Apples, particularly the skin, are known to contain significant amounts of quercetin.

Source: “Comparison of bioactive compounds and health promoting properties of fruits and leaves of apple, pear and quince” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8511160/

Claim: Red onions contain higher amounts compared to white or yellow onions.
Fact check: True. Red onions generally contain higher levels of quercetin than white or yellow onions.

The quercetin content in onions varies depending on the variety, and red onions tend to have more than white or yellow onions.

Source: “Onion (Allium cepa L.) is potentially a good source of important antioxidants” https://pubmed.ncbi.nlm.nih.gov/30996417/

Claim: Leafy greens such as kale and spinach are also good sources.
Fact check: True. Kale and spinach are good sources of quercetin.

Leafy green vegetables, including kale and spinach, contain quercetin, although often less than onions or apples.

Source: “Transepithelial Anti-Neuroblastoma Response to Kale among Four Vegetable Juices Using In Vitro Model Co-Culture System” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7913023/

Claim: Berries, particularly blueberries and cranberries, are additional providers of this flavonoid.
Fact check: True. Berries, including blueberries and cranberries, contain quercetin.

Various berries, including blueberries and cranberries, are sources of quercetin, but levels vary widely.

Source: “Natural Functional Beverages as an Approach to Manage Diabetes” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10707707/

Claim: Generally speaking, the more vibrant the color of a fruit or vegetable, the more quercetin it contains.
Fact check: Generally true. More vibrant color often correlates with higher quercetin content.

The intensity of color in fruits and vegetables is often associated with higher concentrations of phytochemicals, including quercetin.

Source: “Structures and Anti-Allergic Activities of Natural Products from Marine Organisms” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10056057/

Claim: Cooking can cause a reduction in the amount of quercetin present in foods.
Fact check: True. Cooking can reduce quercetin content in foods.

Heat exposure from cooking can degrade quercetin, leading to a reduction in its content.

Source: “Impact of thermal processing on polyphenols, carotenoids, glucosinolates, and ascorbic acid in fruit and vegetables and their cardiovascular benefits” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11605278/

Claim: For instance, microwaving tends to retain more quercetin compared to boiling.
Fact check: True. Microwaving often preserves more quercetin compared to boiling.

Microwaving tends to preserve more nutrients, including quercetin, because it uses less water and shorter cooking times compared to boiling.

Source: “Harmony in Motion: Unraveling the Nexus of Sports, Plant-Based Nutrition, and Antioxidants for Peak Performance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11047508/

Claim: It helps protect cells from the harm caused by unstable molecules known as free radicals.
Fact check: True. Quercetin helps protect cells from free radical damage.

Quercetin’s antioxidant properties enable it to neutralize free radicals, protecting cells from oxidative damage.

Source: “The Therapeutic Effects and Mechanisms of Quercetin on Metabolic Diseases: Pharmacological Data and Clinical Evidence” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8249127/

Claim: The antioxidant actions of quercetin might be helpful in preventing chronic illnesses.
Fact check: Potentially True. Quercetin’s antioxidant properties may contribute to the prevention of chronic diseases.

The antioxidant and anti-inflammatory properties of quercetin may help in the prevention of chronic diseases like heart disease and cancer.

Source: “A critical evaluation of risk to reward ratio of quercetin supplementation for COVID‐19 and associated comorbid conditions” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9111035/

Claim: Research has demonstrated that quercetin can effectively neutralize a broad spectrum of free radicals.
Fact check: True. Quercetin can neutralize a broad range of free radicals.

Quercetin is known for its broad-spectrum antioxidant activity, allowing it to neutralize various types of free radicals.

Source: “Quercetin Preserves Oral Cavity Health by Mitigating Inflammation and Microbial Dysbiosis” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8663773/

Claim: In some instances, it has shown to be more effective than other antioxidants, like vitamin C.
Fact check: Potentially True. Some studies suggest that quercetin may be more effective than vitamin C in certain antioxidant actions.

Studies comparing the antioxidant activities of quercetin and vitamin C have shown that quercetin can sometimes be more potent under specific conditions or with specific free radicals.

Claim: Quercetin has shown potential in reducing inflammation throughout the body.
Fact check: True. Quercetin has demonstrated anti-inflammatory properties.

Quercetin has demonstrated anti-inflammatory effects in numerous studies, reducing inflammation in various body systems.

Source: “Small molecule compounds with good anti-inflammatory activity reported in the literature from 01/2009 to 05/2021: a review” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8516162/

Claim: This flavonoid functions by inhibiting certain enzymes involved in inflammation.
Fact check: True. Quercetin can inhibit inflammatory enzymes.

Quercetin reduces inflammation by inhibiting the activity of enzymes, such as COX and LOX, which are involved in inflammatory pathways.

Source: “Impact of curcumin, quercetin, or resveratrol on the pathophysiology of endometriosis: A systematic review.” https://pubmed.ncbi.nlm.nih.gov/35583746/

Claim: Studies suggest quercetin might provide support for inflammatory bowel diseases and could potentially alleviate the symptoms of rheumatoid arthritis.
Fact check: Potentially True. Research suggests quercetin may help with inflammatory bowel diseases and rheumatoid arthritis symptoms, but more research is needed.

Some studies suggest that quercetin may have beneficial effects in reducing symptoms and inflammation in inflammatory bowel diseases and rheumatoid arthritis, but more robust, large-scale clinical trials are needed to confirm these results.

Source: “Phenolic Compounds Impact on Rheumatoid Arthritis, Inflammatory Bowel Disease and Microbiota Modulation” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7912052/

Claim: It works by stabilizing mast cells, which release histamine during allergic responses.
Fact check: True. Quercetin stabilizes mast cells, reducing histamine release.

Quercetin helps to stabilize mast cells, which reduces the release of histamine and other compounds that trigger allergic responses.

Source: “Structures and Anti-Allergic Activities of Natural Products from Marine Organisms” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10056057/

Claim: This may be beneficial for individuals with asthma or other respiratory allergies.
Fact check: Potentially True. Quercetin may help with respiratory allergies and asthma, but more research is required.

By reducing inflammation and histamine release, quercetin may help to alleviate respiratory symptoms associated with allergies and asthma. However, results from studies vary and more research is needed.

Source: “A Systematic Review: Quercetin—Secondary Metabolite of the Flavonol Class, with Multiple Health Benefits and Low Bioavailability” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11594109/

Claim: Some research indicates that quercetin could be as effective as certain allergy medications.
Fact check: Potentially True. Some studies suggest that quercetin may have comparable effectiveness to some allergy medications but more research is required.

Some preliminary research suggests quercetin may have similar effectiveness to certain antihistamines or mast cell stabilizers in reducing allergy symptoms, but additional, more comprehensive studies are needed.

Source: “Evaluation of combined famotidine with quercetin for the treatment of peptic ulcer: in vivo animal study” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4403742/

Claim: It might contribute to lowering blood pressure and decreasing the risk of heart disease.
Fact check: Potentially True. Quercetin may help to lower blood pressure and reduce heart disease risk, though more research is required.

Some studies suggest that quercetin may have a beneficial effect on reducing blood pressure and other risk factors associated with heart disease. However, these results are preliminary, and more robust studies are needed.

Source: “Decreased blood pressure with acute administration of quercetin in L‐NAME‐induced hypertensive rats” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11659105/

Claim: Research suggests that quercetin may improve blood flow and reduce stiffness in the arteries.
Fact check: Potentially True. Quercetin may improve blood flow and reduce arterial stiffness.

Some studies show that quercetin can improve endothelial function and reduce arterial stiffness, leading to improved blood flow, but more long-term trials are required.

Source: “Decreased blood pressure with acute administration of quercetin in L‐NAME‐induced hypertensive rats” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11659105/

Claim: Additionally, it could help lower levels of LDL, often referred to as “bad” cholesterol.
Fact check: Potentially True. Quercetin may help reduce LDL cholesterol levels.

Some studies suggest that quercetin may contribute to lowering LDL cholesterol levels, which can reduce the risk of heart disease, however the effects may be minimal.

Source: “Efficacy and safety of dietary polyphenols in rheumatoid arthritis: A systematic review and meta-analysis of 47 randomized controlled trials” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10073448/

Claim: One specific study showed that it lowered systolic blood pressure by approximately 5 mm Hg and diastolic blood pressure by about 2.6 mm Hg.
Fact check: Potentially True. Some studies show quercetin lowered systolic blood pressure by approximately 5 mm Hg and diastolic blood pressure by about 2.6 mm Hg, but these results may vary.

While some studies have shown these results, the effects may vary depending on factors such as the dose and individual differences. The results may not be generalizable to all populations and more robust research is needed.

Source: “Decreased blood pressure with acute administration of quercetin in L‐NAME‐induced hypertensive rats” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11659105/

Claim: It possesses antiviral characteristics and may help the body combat infections.
Fact check: Potentially True. Quercetin shows antiviral properties.

Quercetin has demonstrated antiviral properties in some studies, but more research is necessary to confirm the effectiveness and mechanisms of action against viral infections.

Source: “Health Benefits of Quercetin in Age-Related Diseases” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9032170/

Claim: This flavonoid also supports the production and activity of immune cells.
Fact check: Potentially True. Quercetin may support immune cell function.

Some studies suggest that quercetin can enhance the function of various immune cells, but more research is necessary to confirm the findings.

Source: “Quercetin: A Functional Food-Flavonoid Incredibly Attenuates Emerging and Re-Emerging Viral Infections through Immunomodulatory Actions” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9920550/

Claim: Research has shown that quercetin can inhibit the replication of various viruses.
Fact check: Potentially True. Research has shown quercetin can inhibit the replication of some viruses in vitro.

Quercetin has shown some effectiveness in inhibiting viral replication in vitro, but its clinical efficacy in humans is not fully established.

Source: “Quercetin: A Functional Food-Flavonoid Incredibly Attenuates Emerging and Re-Emerging Viral Infections through Immunomodulatory Actions” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9920550/

Claim: These include influenza viruses and the herpes simplex virus.
Fact check: Potentially True. Quercetin has demonstrated some inhibitory activity against influenza viruses and herpes simplex virus in vitro.

In some lab studies, quercetin has shown the potential to inhibit the replication of viruses like influenza and herpes simplex, but these results are still preliminary, and more human trials are needed to confirm these findings.

Source: “Quercetin Preserves Oral Cavity Health by Mitigating Inflammation and Microbial Dysbiosis” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8663773/

Claim: It may also help in reducing the severity and duration of upper respiratory infections.
Fact check: Potentially True. Quercetin may help reduce the severity and duration of upper respiratory infections.

Some studies suggest that quercetin may help with upper respiratory infections by reducing the duration and severity of symptoms, but large, robust trials are needed.

Source: “Flavonoids for Treating Viral Acute Respiratory Tract Infections: A Systematic Review and Meta-Analysis of 30 Randomized Controlled Trials” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8888526/

Claim: For example, combining quercetin with bromelain may enhance its absorption.
Fact check: True. Combining quercetin with bromelain can enhance its absorption.

Bromelain, an enzyme found in pineapple, has been shown to improve the absorption of quercetin, increasing its bioavailability.

Source: “Quercetin in men with category III chronic prostatitis: a preliminary prospective, double-blind, placebo-controlled trial” https://pubmed.ncbi.nlm.nih.gov/10604689/

Claim: Liposomal formulations are designed to increase bioavailability.
Fact check: True. Liposomal formulations are designed to improve bioavailability.

Liposomal formulations encapsulate quercetin, enhancing its absorption and bioavailability.

Source: “A nano-Liposomal formulation potentiates antioxidant, anti-inflammatory, and fibrinolytic activities of Allolobophora caliginosa coelomic fluid: formulation and characterization” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10401763/

Claim: Look for products from well-known manufacturers.
Fact check: True. It is advisable to choose supplements from well-known manufacturers.

Choosing products from reputable manufacturers can often ensure higher product quality and reduce risk.

Claim: Also, verify if the supplement contains any extra ingredients that might cause sensitivity.
Fact check: True. It is important to check for added ingredients that may cause sensitivity.

Checking supplement labels for added ingredients can help avoid products that may cause allergic reactions or sensitivities.

Claim: Some individuals take quercetin in divided doses throughout the day.
Fact check: True. Taking quercetin in divided doses may help maintain consistent blood levels.

Some individuals prefer to take quercetin in divided doses to help maintain stable levels throughout the day and potentially enhance its efficacy.

Claim: Some research suggests it might enhance exercise performance and recovery.
Fact check: Potentially True. Some research suggests quercetin may improve exercise performance and recovery, but results are mixed.

Some studies suggest quercetin may have beneficial effects on exercise performance and muscle recovery, however results vary across individuals and further research is needed to confirm the findings.

Source: “Effect of Quercetin Treatment on Mitochondrial Biogenesis and Exercise-Induced AMP-Activated Protein Kinase Activation in Rat Skeletal Muscle” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7146161/

Claim: Some indicate it might improve VO2 max, which measures aerobic capacity.
Fact check: Potentially True. Some studies suggest quercetin may improve VO2 max.

Some research indicates that quercetin supplementation may improve VO2 max, which is a measure of aerobic capacity. However, these results are not consistent, and more studies are necessary.

Source: “The effect of quercetin and citrulline on cycling time trial performance” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11488173/

Claim: Quercetin may help reduce inflammation and oxidative stress that can occur after exercise.
Fact check: True. Quercetin may reduce inflammation and oxidative stress after exercise.

Quercetin’s anti-inflammatory and antioxidant properties can help in reducing exercise-induced muscle damage and oxidative stress, potentially aiding in recovery.

Source: “Antioxidant supplements and endurance exercise: Current evidence and mechanistic insights” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7284926/

Claim: The benefits might be more apparent in those who are untrained or new to intense exercise.
Fact check: Potentially True. The benefits of quercetin on exercise performance may be more pronounced in untrained individuals.

Some studies suggest that untrained individuals may see more benefits from quercetin supplementation than trained athletes. Elite athletes may not see as much improvement due to their already optimized performance levels.

Source: “Quercetin: A Potential Polydynamic Drug” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10745404/

Claim: Quercetin could potentially interact with blood thinners like warfarin. It may increase the risk of bleeding.
Fact check: True. Quercetin may interact with blood thinners like warfarin, potentially increasing bleeding risk.

Quercetin’s potential to affect blood clotting can increase bleeding risk when used with anticoagulants. It’s essential to consult with a healthcare provider before using it with blood thinners.

Source: “Improvement of Therapeutic Value of Quercetin with Chitosan Nanoparticle Delivery Systems and Potential Applications” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9959398/

Claim: This flavonoid might also affect how the body processes certain antibiotics.
Fact check: Potentially True. Quercetin may interact with some antibiotics.

Quercetin may interact with certain antibiotics, potentially altering their effectiveness or metabolism. It’s essential to discuss with a healthcare professional about potential interactions.

Source: “Surface modified niosomal quercetin with cationic lipid: an appropriate drug delivery system against Pseudomonas aeruginosa Infections” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11167023/

Claim: The same is true for some chemotherapy drugs.
Fact check: Potentially True. Quercetin may interact with some chemotherapy drugs.

Quercetin can potentially interact with chemotherapy drugs, affecting their efficacy or causing adverse effects. Consulting with an oncologist is essential when taking quercetin supplements alongside chemotherapy.

Source: “Quercetin: A Potential Polydynamic Drug” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10745404/

Claim: Quercetin may interact with medications that are metabolized by the liver.
Fact check: True. Quercetin can interact with medications metabolized by the liver.

Quercetin may affect liver enzymes, potentially interacting with numerous medications processed by the liver. It may either enhance or reduce their effects. It’s crucial to consult with a healthcare provider to identify potential interactions.

Source: “A Systematic Review: Quercetin—Secondary Metabolite of the Flavonol Class, with Multiple Health Benefits and Low Bioavailability” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11594109/

Claim: Most side effects are mild and tend to resolve on their own.
Fact check: True. Side effects of quercetin are usually mild and temporary.

Most individuals taking quercetin supplements will experience mild side effects, such as nausea or headache, which tend to resolve on their own. More severe side effects are rare.

Source: “The potential anti-cancer effects of quercetin on blood, prostate and lung cancers: An update” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10011078/

Claim: In rare cases, quercetin might cause more severe side effects. These could include kidney problems or allergic reactions.
Fact check: Potentially True. Rarely, quercetin may cause more severe side effects such as kidney problems or allergic reactions.

In rare cases, quercetin has been linked with more severe side effects such as kidney problems or allergic reactions. It is important to monitor symptoms and seek medical attention if serious symptoms occur.

Source: “The potential anti-cancer effects of quercetin on blood, prostate and lung cancers: An update” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10011078/

Claim: Researchers are investigating its potential advantages for various health conditions.
Fact check: True. Quercetin’s potential health benefits are being widely studied.

Researchers are conducting numerous studies to understand quercetin’s potential benefits for different health conditions, including cancer, heart disease, and neurological disorders.

Claim: Some research indicates it might help in preventing certain forms of cancer.
Fact check: Potentially True. Some research suggests quercetin may help in cancer prevention, but more studies are needed.

Some studies indicate quercetin may have anti-cancer properties, potentially preventing certain types of cancer. More research and human trials are still needed to confirm these findings.

Source: “Targets Involved in the Anti-Cancer Activity of Quercetin in Breast, Colorectal and Liver Neoplasms” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9918234/

Claim: It may also enhance the effectiveness of some chemotherapy drugs.
Fact check: Potentially True. Quercetin may enhance the effectiveness of some chemotherapy drugs, but further research is necessary.

Quercetin may have potential to enhance the effects of some chemotherapy drugs, but the results are still preliminary. It is important to consult an oncologist before using quercetin during chemotherapy.

Source: “Herbal Medicines as Adjuvants for the Treatment of Chemotherapy-Induced Diarrhea.” https://pubmed.ncbi.nlm.nih.gov/37592799/

Claim: Researchers are also examining the neuroprotective characteristics of quercetin.
Fact check: True. Researchers are examining quercetin’s neuroprotective properties.

Scientists are researching the neuroprotective properties of quercetin, and its potential to prevent or slow the progression of neurodegenerative diseases.

Source: “The Potential Benefits of Quercetin for Brain Health: A Review of Anti-Inflammatory and Neuroprotective Mechanisms” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10094159/

Claim: Studies relating to Alzheimer’s and Parkinson’s disease are ongoing.
Fact check: True. Research into quercetin’s potential benefits for Alzheimer’s and Parkinson’s is underway.

Ongoing studies are investigating the potential of quercetin in preventing or slowing the progression of neurodegenerative diseases such as Alzheimer’s and Parkinson’s.

Source: “Quercetin as a JAK–STAT inhibitor: a potential role in solid tumors and neurodegenerative diseases” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9327369/

Claim: The antiviral properties of quercetin are another area of interest.
Fact check: True. Quercetin’s antiviral properties are an area of active research.

Researchers are actively investigating the potential of quercetin as an antiviral agent, including its effects against various viruses such as influenza and coronavirus.

Source: “Quercetin: A Functional Food-Flavonoid Incredibly Attenuates Emerging and Re-Emerging Viral Infections through Immunomodulatory Actions” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9920550/

Claim: While initial findings are promising, more research is necessary to confirm these effects.
Fact check: True. More research is required to confirm the antiviral effects of quercetin.

While preliminary results are promising, more studies are necessary to confirm the antiviral effects of quercetin and their clinical applications.

Claim: Don’t focus exclusively on foods rich in quercetin.
Fact check: True. Focusing on a balanced diet is more important than focusing solely on quercetin.

It’s essential to maintain a balanced diet rather than focusing on individual foods rich in quercetin for optimal health.

Claim: Instead, aim for a balanced diet with lots of fruits and vegetables.
Fact check: True. A balanced diet with plenty of fruits and vegetables is beneficial.

Consuming a wide range of fruits and vegetables provides a multitude of essential nutrients, including antioxidants, which are necessary for overall health.

Claim: whole food sources are often the better choice.
Fact check: True. Whole food sources of quercetin are often preferable to supplements.

Whole food sources of nutrients are usually better than supplements, as they also provide a range of other vitamins, minerals, and fiber. These act synergistically to promote overall health.

Claim: Typical doses range from 500-1000 mg per day.
Fact check: True. Typical supplemental doses of quercetin range from 500-1000 mg per day.

The typical supplemental dosage for quercetin ranges between 500-1000 mg per day but can vary, it is always best to discuss with a health care professional before starting new supplements

Claim: Some studies suggest quercetin may help reduce allergy symptoms.
Fact check: Potentially True. Some studies suggest quercetin may alleviate allergy symptoms.

Studies suggest quercetin may have anti-allergic properties, helping to reduce allergy symptoms, however more research is needed to confirm the findings and understand the mechanisms.

Source: “Abstracts TPS” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7463038/

Claim: It works by stabilizing mast cells and reducing inflammation.
Fact check: True. Quercetin works by stabilizing mast cells and reducing inflammation.

Quercetin stabilizes mast cells, reducing the release of histamine, and also reduces inflammation, which may alleviate allergy symptoms.

Source: “LC-MS/MS metabolomics-facilitated identification of the active compounds responsible for anti-allergic activity of the ethanol extract of Xenostegia tridentata” https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9012362/


Medically reviewed and fact checked

Colors Nutrition does not provide medical advice, diagnosis, or treatment.