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Categories · Quercetin

10 Best Quercetin 2026

We compared the top Quercetin products so you can quickly spot the strongest options for value, features, and everyday performance.

Last Updated: August 2026 · By BuyersGreatGuide Team
2
Popular Nutricost Quercetin 880mg with Bromelain, 240 Vegetarian

Nutricost Quercetin 880mg with Bromelain, 240 Vegetarian

A balanced choice for shoppers who want strong features without overspending.
  • High potency 880mg of quercetin per serving.

  • Includes bromelain for enhanced absorption.

  • Gluten-free and non-GMO formulation.

9.6 / 10 Rating
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3
Best Deal ASquared Nutrition Quercetin 500mg Supplement

ASquared Nutrition Quercetin 500mg Supplement

A smart value pick for buyers focused on savings and practical performance.
  • High potency with 500mg per serving.

  • Supports cardiovascular and immune health.

  • Contains Quercetin Dihydrate for better absorption.

9.3 / 10 Rating
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4
Luma Nutrition Quercetin 500mg with Bromelain

Luma Nutrition Quercetin 500mg with Bromelain

  • Combines quercetin and bromelain for enhanced benefits.

  • Supports immune health with powerful antioxidants.

  • Easy to swallow and well-tolerated.

8.8 / 10 Rating
$2 Coupon Check Price
5
Klaire Labs Quercetin-Bromelain Forte Immune Support Enzymes

Klaire Labs Quercetin-Bromelain Forte Immune Support Enzymes

  • Combines quercetin with supportive enzymes.

  • Promotes immune and seasonal support naturally.

  • Free from common allergens and additives.

8.6 / 10 Rating
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6
XYMOGEN Quercetin 20× Plus Respiratory Support Supplement

XYMOGEN Quercetin 20× Plus Respiratory Support Supplement

  • Combines quercetin with Vitamin C and NAC.

  • Vegan and gluten-free formulation.

  • Specifically designed for respiratory support.

8.5 / 10 Rating
10% Coupon Check Price
7
NutraMedix Quercetin Antioxidant & Immune Support Supplement

NutraMedix Quercetin Antioxidant & Immune Support Supplement

  • Supports heart health and immune function.

  • Enhances zinc and vitamin C absorption.

  • Vegetarian-friendly with no artificial additives.

8.2 / 10 Rating
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8
Quercetin with Bromelain, Vitamin C, Zinc, and Organic Whole Food Blend - 1215mg, Phytosome Quercetin 500mg with Ginger and Flavonoids for Immune Support - 180 count
  • Combines quercetin, bromelain, vitamin C, and zinc.

  • Includes organic whole food quercetin blend.

  • Supports immune health with added ginger and flavonoids.

8 / 10 Rating
30% Coupon Check Price
9
ASquared Nutrition Quercetin 1000mg with Zinc

ASquared Nutrition Quercetin 1000mg with Zinc

  • High-strength 1000mg quercetin per serving.

  • Includes immune-boosting zinc and elderberry.

  • 120 servings for extended use.

7.8 / 10 Rating
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10
Micro Ingredients Quercetin Vitamin C Zinc Immune Support

Micro Ingredients Quercetin Vitamin C Zinc Immune Support

  • Comprehensive immune support with three key nutrients.

  • High bioavailability from diverse zinc forms.

  • Convenient 240 servings offer long-lasting supply.

7.7 / 10 Rating
10% off + 10% Coupon Check Price

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Quercetin Supplements: Key Considerations

Quercetin is a plant-derived flavonoid available in capsule form, typically as a powdered supplement like quercetin dihydrate or as an absorption-enhanced formulation such as a phytosome. The evidence regarding its effectiveness varies and depends on the specific formulation. Some clinical trials and reviews report modest benefits for blood pressure regulation or certain seasonal eye and nasal symptoms. However, a large trial examining respiratory infections found no overall reduction in infection rates at doses of 500 or 1,000 mg daily. Therefore, when choosing a quercetin supplement, focus on the evidence supporting its specific form, dosage, and duration—rather than broad claims about immune support, allergy relief, infection prevention, or cardiovascular health.

Begin by examining the Supplement Facts panel. An informative label will specify the form of quercetin, the amount per serving, serving size, daily usage instructions, and all active ingredients. A listed dose of “1,000 mg” may refer to the weight of the powder or complex, not the actual quercetin content; for example, some products list 1,000 mg of a powder that provides only 18% pure quercetin, while others specify 250 mg of a phospholipid complex without indicating the exact quercetin amount. If the product combines multiple ingredients, such as bromelain, zinc, vitamin C, nettle, elderberry, or ginger, it should disclose each component’s individual quantity. Proprietary blends may make it difficult to assess ingredient interactions and potential redundancies.

Top Quercetin

Pay close attention to absorption claims. Human pharmacokinetic studies support higher absorption levels for products using Quercetin Phytosome technology, but this does not mean all products labeled “high absorption,” “bioavailable,” or claiming “50×” absorption are equivalent. Look for human studies verifying the specific delivery technology at a comparable dose. Bromelain is sometimes marketed as an absorption enhancer, but reviews have not found product-specific pharmacokinetic evidence supporting this claim.

Quality assurance claims should reference the finished capsule, not just raw ingredients, manufacturing sites, or vague “third-party testing” statements. The most reliable evidence includes current lot-specific assays like HPLC for quercetin content, ICP-MS results for heavy metals, and certification from ISO/IEC 17025-accredited laboratories. A certificate of analysis should specify the lot number, testing methods, laboratory, and quantitative results. Disintegration tests (USP <2040>) or equivalent procedures for verifying proper capsule release are important because raw ingredient documentation doesn’t confirm that the finished capsule releases its contents properly. GMP certification from organizations like NSF can indicate manufacturing quality, but they do not certify individual bottles. Public listings from USP, NSF, ConsumerLab, Informed Sport, or similar organizations are meaningful only if they verify the exact product in question.

Marketing claims should reflect the scientific evidence. Avoid language suggesting quercetin can prevent or treat allergies, infections, COVID-19, cancer, or heart disease. Verify product traceability by checking for accurate labeling of the responsible company, contact details, complete ingredient list, lot and expiration dates, and consistency between online descriptions and the physical product. Many products use standard bottles or pouches that lack verified information about recycled content, resin type, recycling instructions, or disposal guidance.

Safety considerations are equally important. Quercetin may influence drug metabolism or transport, potentially affecting medication levels—reviewers often recommend consulting with a healthcare professional. Bromelain and other proteolytic enzymes carry allergy risks (particularly for pineapple allergy), as well as concerns related to bleeding, surgery, and gastrointestinal issues. Zinc can interfere with certain antibiotics and penicillamine; some products supply 50 mg daily, exceeding the adult upper limit of 40 mg, while others provide 30 mg or 22 mg. Vitamin D3 at 5,000 IU, as found in some combinations, exceeds the recommended upper limit of 4,000 IU for adults. Pregnant or breastfeeding individuals, children, those with kidney disease or kidney-stone history, and anyone on prescription medications should seek personalized advice from a healthcare provider instead of relying solely on label warnings. Quercetin supplements are not a substitute for medical evaluation or treatment for ongoing allergy, respiratory, infectious, or cardiovascular conditions.

Integrity

These topics clarify what the provided scores indicate: accurate dosing, credible claims, evidence based on the finished product, responsible warnings, and packaging information that can be verified. A high score signifies well-documented, product-specific information; however, it does not guarantee that quercetin will deliver a specific health benefit.

HHealth & Safety

Health benefits for humans at the specified dose

This assesses whether human studies support the product’s claimed benefits when using the same form, dosage, and duration of quercetin. The evidence regarding quercetin is mixed: while some studies show modest effects on blood pressure or seasonal symptoms, they do not confirm immune or infection prevention. Products with higher scores typically employ doses and forms similar to those used in reputable human trials, whereas lower-scoring products tend to make broad claims that lack supporting comparable evidence.

Absorption claim supported by human data

This assesses whether a claimed enhanced absorption is backed by human pharmacokinetic testing of the specific technology and a comparable dosage. The products evaluated included plain powders as well as branded phytosome systems. Higher ratings were awarded to products utilizing a validated Quercetin Phytosome technology, while lower scores were given to claims that bromelain, dihydrate, citrus compounds, or a generic “bioavailable” label enhance absorption without supporting evidence.

Medications, Pregnancy, and Safety Precautions

This assessment determines whether the label explicitly covers adult use, medications, pregnancy or breastfeeding, allergies, and guidance on when to seek medical advice. This is important because quercetin may influence how drugs are processed, and higher doses along with added botanicals or enzymes raise additional safety considerations. Labels with higher scores specify particular medication categories or include clear exclusions, whereas lower-scoring labels tend to use general language about consulting a healthcare professional and often omit warnings related to pregnancy, allergies, bleeding, or surgery.

A secure and completely transparent combination formula

This assesses whether additional ingredients are properly dosed, suitable for regular use, and free from hidden redundancies or unknown risks. Quercetin products may include ingredients such as zinc, vitamin C, bromelain, nettle, elderberry, ginger, or enzymes. Higher ratings are given to products that use simple, fully specified formulas; lower ratings indicate complex mixtures, unclear potency, animal-derived ingredients, or doses that may be significant when taken with other supplements.

The capsule or tablet is released correctly.

This test demonstrates that the finished capsule dissolves properly and releases its contents as intended. Simply verifying ingredient identity or listing a GMP-certified facility does not provide this information. Most products received similar scores because there was no publicly available record of their disintegration performance. The exception was a higher-scoring product that had a published lot certificate indicating it passed the USP <2040> disintegration test.

Tested for heavy metals, microorganisms, and concealed drugs

This assessment covers recent testing of finished products for metals, microbes, relevant residues, and undeclared drugs, including details about the testing methods and laboratories used. Products with higher scores published lot-specific HPLC or ICP-MS results and provided numerical data on metal levels. Lower scores were assigned to products that only included manufacturer testing statements, relied on pass/fail graphics without laboratory or lot information, or lacked publicly available contaminant reports. No product-specific FDA alerts were found in the reviews provided.

EEcology

Waste-reducing, genuinely labeled packaging

This evaluates whether packaging is minimized and if claims regarding recycled content, recyclability, or disposal can be verified within the United States. The products tested typically used standard bottles, with one pouch, but none had a verified recycling pathway, confirmed recycled content percentage, or environmental certification. As a result, the scores were closely grouped: a higher score indicates fewer unsupported claims, but does not necessarily mean the package has a lower environmental impact.

EEvidence

Confirmed the identity of quercetin and its labeled potency.

This test provides independent verification of the specific form and quantity of quercetin in the final product. Products that scored higher often used a lot-specific HPLC assay to differentiate between forms such as anhydrous or dihydrate quercetin. A historical market analysis revealed significant potency issues with one product, highlighting that a manufacturer's label or generic claim of “95%” is not a substitute for current finished-product verification.

Authentic Independent Product Verification

This assesses whether the finished supplement is verified through a reputable independent certification or market-based testing program that evaluates its identity, potency, and contaminants. Merely having Facility GMP registration is insufficient. Most of the products examined did not have publicly available listings from organizations like USP, NSF, ConsumerLab, Informed Sport, or equivalent certifications. While published lot reports slightly improved some scores, they do not replace ongoing certification.

Claims are supported by the evidence.

This assesses whether marketing employs modest language focused on structure and function rather than suggesting treatment or prevention of disease. Products with higher scores tend to make more restrained claims, whereas those with lower scores promote benefits related to allergy, immune, respiratory, infection, anti-aging, or cardiovascular health beyond what is supported by human evidence. Including a mandatory supplement disclaimer does not validate any unsupported disease-related claims.

Full labeling and responsible seller

This assesses whether consumers can determine the responsible company, product forms and doses, serving sizes, additional ingredients, lot and expiration information, and a reliable contact. Products with higher scores featured clear packaging labels, domestic contact details, and consistent usage instructions. Lower scores indicated issues such as conflicting serving instructions, absent warnings, vague ingredient quantities, or discrepancies between the online listing and the actual packaging.

ForestLeaf Quercetin 500mg with Bromelain, Vitamin C & Stinging Nettle
#1 - Best Overall

ForestLeaf Quercetin 500mg with Bromelain, Vitamin C & Stinging Nettle

Buyer Score 99/100 Integrity Score 72/100 ForestLeaf

Overview

The label provides important accountability information, including a distributor address in Brooklyn, New York, a contact phone number, details on ingredient forms and quantities, additional ingredients, adult usage instructions, and a standard dietary supplement disclaimer. It also notes that the capsules are made of vegetable cellulose and lists microcrystalline cellulose, magnesium stearate, and silicon dioxide as other ingredients. The manufacturer claims the product is non-GMO and free from dairy, gluten, eggs, and nuts. ForestLeaf states that they test each batch for heavy metals, microbiological contaminants, pesticides, and herbicides through independent laboratories. While these are significant quality control claims, specific lot-by-lot reports were not publicly available for verification. No certifications for finished products were found in major independent registries. Additionally, no FDA recall notices or warning letters related to this product were identified in the searches conducted. The packaging appears to use a standard bottle, but there is no verified information regarding recycled content, recyclability, or proper disposal instructions for this product.

What works

  • There was no publicly available lot-specific assay or certificate of analysis to verify the potency of quercetin, detect any contaminants, or confirm the stated activity of bromelain.
  • There are no publicly available certifications such as USP, NSF, Informed Choice, or ConsumerLab, nor any market-purchased test results, for this product.
  • The label and product listing indicate that bromelain enhances absorption; however, no human pharmacokinetic study has been found for this specific bromelain and quercetin formulation.
  • The general medication warning does not explicitly highlight the potential interaction risks related to quercetin, bromelain, and stinging nettle, such as effects with anticoagulants, antiplatelet drugs, diabetes medications, diuretics, and lithium.

What does not

  • All four active ingredients and their respective quantities are listed, with no proprietary blend involved.
  • The label specifies the compound as quercetin dihydrate, rather than leaving the form of quercetin unspecified.
  • The label provides instructions for adults, precautions for pregnancy and nursing, warnings regarding prescription medications, and contact information for the domestic manufacturer.
  • ForestLeaf conducts testing of each batch for heavy metals and microbiological components using independent laboratories.

Who is it for

This product is suitable for adults seeking a standard vegetable capsule formula containing quercetin along with vitamin C, nettle, and bromelain in specified amounts. It is ideal for those who prefer to avoid proprietary blends. The supplement is intended for optional seasonal wellness support and should not replace allergy diagnosis or treatment. A two-capsule serving provides 500 mg of quercetin, a commonly researched supplemental dose, though evidence for its effectiveness in alleviating allergy symptoms remains inconclusive. Additionally, it is suitable for individuals seeking products that are certified gluten-free and dairy-free as stated by the manufacturer.

Who is it not for

This product is not appropriate for self-selection by pregnant or breastfeeding individuals, children, or anyone taking prescription medications without consulting a healthcare professional or pharmacist. Special caution is advised for users of anticoagulants or antiplatelet drugs, diabetes medications, diuretics, lithium, certain antibiotics, immunosuppressants, or cancer treatments, as the ingredients may impact drug effectiveness or absorption. Individuals with a pineapple allergy should avoid formulas containing bromelain. For those who require independently verified potency, contaminant testing, sports certification, or documented disintegration results, it is recommended to select a product with publicly available finished-product verification.

Nutricost Quercetin 880mg with Bromelain, 240 Vegetarian
#2 - Popular

Nutricost Quercetin 880mg with Bromelain, 240 Vegetarian

Buyer Score 96/100 Integrity Score 72/100 Nutricost

Overview

Nutricost offers a straightforward formula instead of a proprietary blend. According to the current manufacturer information, each serving contains 880 mg of quercetin dihydrate and 165 mg of bromelain. The product is packaged in vegetarian capsules and is both gluten-free and non-GMO. The company also states that their products undergo testing by an independent accredited laboratory. While Nutricost Manufacturing is listed in NSF's GMP facility database, this confirms GMP certification for the manufacturing facility itself, not the identity, potency, or contamination levels of the finished product. Safety literature indicates that most adverse effects from quercetin are mild and short-term. However, there are potential interactions with medications and limited data on the long-term safety of high doses. Bromelain considerations include pineapple allergies and medication interactions. No FDA recalls, warning letters, or notices regarding contamination have been associated with this product based on available FDA sources. The supplement comes in standard packaging, and there are no claims regarding recycled materials, recyclability, or environmentally friendly disposal, so its environmental impact in terms of waste cannot be confirmed.

What works

  • There is currently inconclusive evidence regarding broad immune, allergy, or cardiovascular benefits at this specific formula and dosage, and this product has not been subjected to clinical studies.
  • Quercetin may pose potential drug interaction risks, while bromelain could introduce additional medication and allergy considerations. The online product information reviewed does not prominently include detailed guidance on pregnancy, breastfeeding, anticoagulants, or prescription medications.
  • Nutricost asserts that their products undergo testing at independent, accredited laboratories. However, a recent, lot-specific finished-product report verifying the potency of quercetin, bromelain activity, as well as levels of metals and microbes, was not publicly accessible.
  • This product does not have any public certification such as USP, NSF Dietary Supplement, Informed Sport, or similar for finished products. Additionally, having a GMP facility listing is not equivalent to verifying the finished product.
  • There is no disintegration or dissolution report available for the finished product, so the proper capsule release has not been independently documented.

What does not

  • The formula clearly specifies 880 mg of quercetin dihydrate and 165 mg of bromelain per daily serving, with no proprietary blend included.
  • The daily intake of 880 mg of quercetin is nearly equivalent to the 1,000 mg dose used in most studies included in a systematic review on the recovery from exercise-induced muscle damage.
  • The capsule is suitable for vegetarians, and its inactive ingredients are limited to hypromellose, vegetable-derived magnesium stearate, and silica.
  • The package contains 240 capsules, offering 120 servings if taken once daily, providing a convenient four-month supply when used as directed.

Who is it for

This product is suitable for adults seeking a high-dose, pure quercetin dihydrate formula with a clearly measured amount of bromelain, rather than a multi-ingredient allergy blend. It is ideal for vegetarians or those avoiding gluten who prefer capsules and plan to take two capsules daily for several months. The primary evidence-based use case is for adults interested in using quercetin as an supplement around intense exercise, noting that most supporting studies used approximately 1,000 mg per day and did not test this specific finished product.

Who is it not for

This is not a casual or over-the-counter option for individuals taking prescription medications, particularly those with narrow therapeutic windows or drugs influenced by metabolic enzymes and transporters, unless reviewed by a pharmacist or healthcare professional. Do not self-treat persistent allergy, respiratory, infection, or cardiovascular symptoms with this product. Individuals with pineapple allergies, a history of supplement reactions, kidney disease, those who are pregnant or breastfeeding, planning surgery, or taking anticoagulant or antiplatelet medications should seek care from a healthcare provider or choose a product with clearer safety information. Additionally, this product is not suitable for buyers who require publicly verified lot-specific potency or contaminant testing results.

ASquared Nutrition Quercetin 500mg Supplement
#3 - Best Deal

ASquared Nutrition Quercetin 500mg Supplement

Buyer Score 93/100 Integrity Score 67/100 ASquared Nutrition

Overview

The overall health profile of the product presents a mixed picture. The manufacturer states that each vegetarian capsule contains 500 mg of quercetin dihydrate and notes that the product is produced in the United States. It is described as vegan, non-GMO, gluten-free, soy-free, preservative-free, GMP certified, and tested by an ISO 17025-certified laboratory. However, these are manufacturer claims and are not backed by publicly verifiable finished-product certifications or current batch data. Human studies have not documented significant adverse effects at doses up to 1,000 mg daily for up to 12 weeks. Nonetheless, quercetin may influence drug-metabolizing enzymes and could potentially enhance the effects of blood-pressure-lowering medications. There is limited safety information regarding use during pregnancy and breastfeeding. An important consideration is the previous low-potency result from an older batch of the product in 2022, which highlights issues related to quality control. Additionally, there is no verified information on the packaging materials, recycled content, recyclability instructions, or any environmental certifications specific to the product, leaving its environmental impact and disposal options unclear.

What works

  • The potency of the current finished product has not been independently verified through a public lot-specific assay.
  • A market-available test conducted in 2022 on an older aSquared 120-capsule product found that it contained approximately 19% of the labeled quercetin amount. This represents a specific historical quality issue and does not necessarily reflect the quality of every current bottle.
  • The brand's generic third-party testing statement does not specify the current batch, laboratory report details, testing methods, or contaminant findings.
  • Marketing covers benefits related to immunity, cardiovascular health, skin, mood, energy, allergies, and inflammation. However, human evidence at this dosage is mixed or limited for many of these applications.
  • Public product information does not clearly outline warnings regarding medication interactions or precautions for pregnancy and breastfeeding, despite relevant concerns related to quercetin.

What does not

  • The single-active formula is designed to prevent the typical accumulation of zinc, enzymes, or botanical extracts.
  • The manufacturer explicitly specifies the form of quercetin, the dosage as 500 mg per capsule, and a total supply of 200 capsules.
  • A daily dose of 500 mg is similar to the amounts used in short-term human studies; however, the potential health benefits are still uncertain.
  • The manufacturer claims that the capsules are suitable for vegans, and free from gluten, soy, and preservatives.

Who is it for

This product is suitable for adults seeking a straightforward, quercetin-only capsule, who prefer to avoid multi-ingredient immune blends, and who value a long-lasting supply of 200 capsules. It is ideal for individuals who recognize that the 500 mg dosage is a manufacturer-reported amount, not independently verified, and who intend to use it as a dietary supplement rather than as a treatment for infections, allergies, heart conditions, or other diagnosed health issues. Consulting a healthcare professional or pharmacist before use is recommended.

Who is it not for

This product is not ideal for individuals who require independently certified verification of identity, potency, contaminant screening, or capsule-release testing for each item. It should not be used as a replacement for medical treatment in cases of respiratory infections, COVID-19, severe allergies, heart disease, or inflammatory conditions. Pregnant or breastfeeding individuals, children, those with kidney disease, and anyone taking prescription medications should consult a healthcare professional before use. Special caution is advised when using with medications such as cyclosporine, pravastatin, fexofenadine, blood pressure medicines, and other drugs that are influenced by metabolic enzymes or transporters.

Luma Nutrition Quercetin 500mg with Bromelain
#4

Luma Nutrition Quercetin 500mg with Bromelain

Buyer Score 88/100 Integrity Score 72/100 Luma Nutrition

Overview

The primary health benefit highlighted by the manufacturer is a transparent, two-ingredient active formula listed on their product page. Luma specifies quercetin as quercetin dihydrate, providing 500 mg of quercetin and 100 mg of bromelain per two-capsule serving, and recommends taking the supplement with food. Their website also warns about possible interactions with blood thinners, blood pressure medications, and antibiotics. Human studies suggest only limited potential benefits, with the strongest evidence indicating small reductions in blood pressure rather than broad immune or allergy-related effects. Luma claims that each batch is independently tested and produced in a GMP-certified, FDA-registered U.S. facility. While these claims are reassuring, no public certificate of analysis, named testing laboratory, searchable certification, or independent market test results for the finished product were found. Additionally, there are no FDA recall notices or warning letters related to this product. The available packaging information does not specify details about bottle resin, recycled content, recycling instructions, or other environmental claims, making it difficult to assess its environmental impact.

What works

  • There is no publicly available lot-specific testing that verifies the finished capsules contain the labeled quantities of quercetin and bromelain.
  • The third-party testing claimed by the manufacturer is self-reported, as no publicly available test report, designated laboratory, or independently verifiable certification for the finished product can be found.
  • Bromelain is believed to aid in absorption; however, there is no human pharmacokinetic data specifically supporting this for the quercetin-dihydrate and bromelain combination.
  • The public safety guidance does not explicitly mention pregnancy, breastfeeding, pineapple or bromelain allergies, kidney disease, or the various medically significant medication risks.
  • There are no publicly available results regarding finished-product disintegration, heavy metals, microbial contamination, pesticides, residual solvents, or adulterants.

What does not

  • The reported daily dose of 500 mg of quercetin aligns with the threshold used in studies demonstrating modest average reductions in blood pressure.
  • The formula specifies that quercetin is in its dihydrate form and explicitly lists 100 mg of bromelain, instead of using a proprietary blend.
  • The manufacturer recommends taking two capsules with food.
  • The manufacturer recommends consulting a healthcare professional before use for individuals taking blood thinners, blood pressure medications, or antibiotics.
  • The product page includes a U.S. phone contact number and details about the recommended daily serving size along with the active ingredients.

Who is it for

This product is ideal for adults seeking a simple, short-term quercetin regimen with a clearly indicated daily dose of 500 mg, without the need for a complex multivitamin. It is most suitable for individuals looking for modest cardiovascular support who understand that human research is limited and that it does not serve as a replacement for treatments for high blood pressure. The 60-capsule bottle with a recommended two-capsule daily dosage provides a one-month supply. It is better suited for those who can confirm medication compatibility with a healthcare professional or pharmacist before beginning use.

Who is it not for

This product is not suitable for pregnant or breastfeeding women, individuals with kidney disease, or those allergic to pineapple, as public guidance does not sufficiently address these situations, and bromelain is derived from pineapple. People taking warfarin or other blood-thinning medications, antiplatelet drugs, blood pressure medicines, tamsulosin, or antibiotics should not rely solely on the brief warning provided on the website. Additionally, it may not be appropriate for buyers who need publicly available batch testing, certified finished-product quality, or verified contaminant levels before using a supplement.

Klaire Labs Quercetin-Bromelain Forte Immune Support Enzymes
#5

Klaire Labs Quercetin-Bromelain Forte Immune Support Enzymes

Buyer Score 86/100 Integrity Score 72/100 SFI Health

Overview

The specified formula includes 500 mg of quercetin dihydrate per two capsules, along with vitamin C, rutin, bromelain, papain, and porcine pancreatin. The manufacturer claims the product is non-GMO and free from several common allergens; however, the label clearly states that it contains lactose and milk. This information is important for individuals with dairy allergies or intolerances. During the review, no publicly available certifications from major organizations such as USP, NSF, or Informed Choice for finished products were confirmed. Additionally, no recent batch certificates were found for verifying identity, heavy metals, microbial contamination, residual solvents, or capsule disintegration. Searches also did not reveal any FDA recalls, warning letters, or listings for contaminated products related to this item. The manufacturer does not provide details about packaging materials, recycled content, recyclability, or disposal practices, making it impossible to assess the environmental impact of the packaging.

What works

  • There is no existing publicly available certificate of analysis to independently verify the potency, contaminants, or capsule release of the finished-product quercetin.
  • There was no evidence of certification from USP, NSF, Informed Choice, or any similar recognized third-party organization for the finished product.
  • The overall immune and cytokine response is more pronounced than the direct evidence supporting this specific combination and dosage.
  • The product contains lactose and is labeled as containing milk, which may conflict with certain retailer allergen information or descriptions.
  • The label recommends consulting a healthcare professional before using with prescription medications but does not explicitly indicate any allergy risks related to pineapple or papaya, concerns regarding anticoagulants, or possible interactions involving quercetin affecting drug transport.

What does not

  • The manufacturer supplies precise quantities, ingredient forms, and activity units for the entire enzyme mixture.
  • A two-capsule serving provides 500 mg of quercetin, which is within the range tested in short-term human studies, although not in this specific formulation.
  • The label specifies the product as quercetin dihydrate and indicates that it is derived from the Japanese pagoda tree.
  • The manufacturer provides warnings regarding pregnancy, breastfeeding, medical conditions, prescription medication use, and consultations for individuals under 18.

Who is it for

This product is intended for adults seeking a multi-ingredient quercetin supplement rather than pure quercetin. It provides a 25 to 50-day supply based on the recommended use. Users should be able to tolerate milk-derived lactose and porcine pancreatin. It is particularly suitable as a clinician-reviewed adjunct for managing seasonal symptoms, especially for those who prefer products with detailed labels indicating specific enzyme activities. However, users should not view it as a replacement for professional treatment of allergies, asthma, infections, or cardiovascular conditions.

Who is it not for

This product is not suitable for individuals with milk allergy, lactose intolerance, pineapple or papaya allergies, or those with dietary restrictions excluding pork-derived ingredients. Children should not initiate use on their own, as the label indicates that pediatric use should be supervised by a healthcare professional. Pregnant or breastfeeding women, individuals with kidney disease or other serious health conditions, those taking prescription medications, or those on anticoagulant or antiplatelet therapy should consult a healthcare provider or pharmacist before use. Additionally, it is not appropriate for buyers who require third-party public certification or batch-specific laboratory testing.

XYMOGEN Quercetin 20× Plus Respiratory Support Supplement
#6

XYMOGEN Quercetin 20× Plus Respiratory Support Supplement

Buyer Score 85/100 Integrity Score 74/100 XYMOGEN

Overview

The formula clearly discloses its four active ingredients along with their daily dosages. Its quercetin delivery system is supported by human pharmacokinetic data, although the primary absorption study was conducted by employees of the ingredient supplier and did not evaluate this specific finished product. The claims regarding respiratory and nasal comfort fall within the structure-function category and include the standard disclaimer that the product is not intended to diagnose, treat, cure, or prevent any disease. The manufacturer provides a general warning about consulting a healthcare professional before use and states that the formula is free from common food allergens and animal-derived ingredients. However, there is no publicly available, lot-specific certificate of analysis for the finished product to confirm its identity, potency, heavy metal levels, microbial safety, or capsule release specifications. Additionally, no independent certification specific to this product could be found. Information about the packaging, including recycled content, recyclability instructions, or environmental claims, was not disclosed, making it difficult to assess the product’s environmental impact.

What works

  • The absorption and symptom research pertain to the quercetin phytosome ingredient itself, not this specific final product combination.
  • There was no publicly available, lot-specific certificate to verify the potency of finished-product quercetin, as well as its metal content, microbial contamination, or capsule release.
  • This product does not have a public certification from USP, NSF, ConsumerLab, Informed Choice, or any other similar independent organization for finished products.
  • The label recommends that individuals on medication consult a healthcare professional, but it does not explicitly highlight considerations related to pregnancy, breastfeeding, kidney disease, or potential drug interactions.
  • Nettle is solely identified as Urtica dioica and/or Urtica urens leaf extract, with no specified standardization marker.

What does not

  • The complete daily formula is revealed, with no proprietary blend hiding the amounts of individual ingredients.
  • The 250 mg dose of quercetin phospholipid corresponds to the dose assessed in a human absorption study using the same phytosome technology.
  • A human trial, using a placebo for comparison and administering a similar 200 mg phytosome dose, observed improvements across various measures of seasonal nasal and eye symptoms.
  • The manufacturer offers guidance on medication interactions, tamper-evidence seal instructions, storage recommendations, and a customer service contact number.
  • The manufacturer claims that the formula does not contain any major food allergens, animal-based ingredients, gluten, or genetically modified components.

Who is it for

This product is ideal for adults seeking a once-daily, precisely dosed quercetin phytosome supplement to help alleviate seasonal nasal or eye discomfort. It also includes moderate amounts of vitamin C, nettle leaf, and N-acetyl-L-cysteine. It is best suited for individuals using it as a supportive supplement rather than a treatment for any medical condition, and who can consult with a pharmacist or healthcare professional about their medications. Each 60-capsule bottle provides a 30-day supply based on the recommended two-capsule daily dose.

Who is it not for

This is not a suitable self-care option during pregnancy or breastfeeding, as the label provides no guidance on pregnancy or lactation, and human safety data for supplement combinations are limited. Individuals with kidney disease, those taking prescription medications—particularly drugs affected by metabolic enzymes or transporters—and anyone using fluoroquinolone antibiotics should consult a healthcare professional before use. Additionally, it does not substitute for medical evaluation in cases of wheezing, shortness of breath, fever, severe allergy symptoms, or persistent respiratory issues.

NutraMedix Quercetin Antioxidant & Immune Support Supplement
#7

NutraMedix Quercetin Antioxidant & Immune Support Supplement

Buyer Score 82/100 Integrity Score 66/100 NutraMedix

Overview

The manufacturer identifies the source as Sophora japonica flower and specifies the ingredient as quercetin dihydrate. They also state that their suppliers and manufacturing processes adhere to current good manufacturing practices, with testing for identity, microbial contamination, and heavy metals conducted both before and after encapsulation. These statements are from the manufacturer and do not include publicly available lot-specific test results. Additionally, there is no specific product listing available through USP Verified, NSF Certified Dietary Supplements, or ConsumerLab certifications. The product page includes warnings regarding use during pregnancy and nursing; however, the consumer directions do not clearly communicate the potential for drug interactions, which are noted in quercetin safety literature. Quercetin has the potential to affect the absorption and effectiveness of certain medications. No FDA recall notices or warning letters specific to this product were identified during the review. The manufacturer claims that the product is made in the U.S., yet their ingredient source page indicates that the quercetin dihydrate is sourced from China. There are no verified claims regarding recycled content, package material specifications, or U.S. disposal guidance.

What works

  • No independent, lot-specific finished-product assay was available to verify the identity of quercetin, its dihydrate form, or the labeled potency of 500 mg.
  • There was no publicly available certificate of analysis for the finished product regarding heavy metals, microbial content, solvents, or capsule disintegration testing.
  • The official retail guidelines advise against use during pregnancy or breastfeeding but do not explicitly highlight the known risk of potential medication interactions.
  • Marketing for immune support and nutrient absorption extends beyond the available human evidence. A 12-week study showed no significant enhancement in various innate immune indicators with daily doses of 500 mg or 1,000 mg.
  • The marketplace description and the manufacturer's Supplement Facts label differ in specifying whether 500 mg corresponds to a single capsule or a serving consisting of two capsules.

What does not

  • The single-active formula prevents the repetitive inclusion of zinc, vitamin C, bromelain, or other added active ingredients in each formulation.
  • The official panel provides the full botanical source name, the amount of quercetin per serving, the serving size, and the inactive ingredients.
  • The designated daily dose of 500 mg falls within the dosage range examined in certain human studies, including those analyzed in meta-analyses related to blood pressure and inflammation.
  • The manufacturer claims that the capsules are suitable for vegetarians and do not contain gluten, soy, dairy, sugar, mold, or yeast.

Who is it for

This product is designed for adults who prefer a straightforward quercetin supplement rather than a multi-ingredient immune support blend and are capable of adhering to the recommended two-capsule daily dose. It may be ideal for individuals who already receive zinc and vitamin C from other sources and wish to avoid overlapping ingredients. The 120-capsule bottle offers a 60-day supply based on the suggested use. While there is human evidence indicating some benefit in modest improvements in blood pressure and inflammatory markers, it is less conclusive regarding reliable immune system enhancement. Therefore, users should have realistic expectations.

Who is it not for

This product is not suitable for pregnant or breastfeeding individuals, those seeking a supplement specifically for children, or those who want a product with publicly available third-party certification and batch-specific laboratory test results. Individuals taking prescription medications should consult a pharmacist or healthcare professional before use, particularly if they are on blood pressure or blood sugar medications, cyclosporine, statins, diclofenac, quetiapine, midazolam, or quinolone antibiotics. People with kidney disease, concerns about estrogen-sensitive cancers, or those requiring confirmed treatments for allergies, infections, or COVID-19 should not depend on this supplement.

Quercetin with Bromelain, Vitamin C, Zinc, and Organic Whole Food Blend - 1215mg, Phytosome Quercetin 500mg with Ginger and Flavonoids for Immune Support - 180 count
#8

Quercetin with Bromelain, Vitamin C, Zinc, and Organic Whole Food Blend - 1215mg, Phytosome Quercetin 500mg with Ginger and Flavonoids for Immune Support - 180 count

Buyer Score 80/100 Integrity Score 72/100 SUPPLEMENTS STUDIO

Overview

The manufacturer claims that the product is vegan, non-GMO, gluten-free, and free from fillers, additives, and preservatives. Its ingredient list includes a sunflower lecithin-quercetin complex derived from Sophora japonica, bromelain from pineapple, zinc picolinate, vitamin C from acerola, ginger, citrus bioflavonoids, and an organic food blend. Additionally, the company provides a contact address and phone number based in the United States. The recommended zinc dose of 15 mg is below the adult upper limit of 40 mg per day; however, total zinc intake from foods and other supplements should also be considered. There is no publicly available evidence of independent certification, lot-specific finished-product testing, or specific testing for capsule disintegration. No FDA recalls, warning letters, or public exposure alerts related to this product have been found in U.S. sources. Information regarding packaging materials, recycled content, recyclability, or disposal instructions has not been verified, making it impossible to assess the product's environmental impact based on the current evidence.

What works

  • The 500 mg label refers to a phospholipid complex, not an individual amount of quercetin.
  • There is no publicly available lot-specific certificate that confirms the identity, potency, heavy metals, microbes, or other contaminants in the finished quercetin capsules.
  • There is no available public independent certification or market-purchased test report for this specific product.
  • The online safety guidance is broad and does not explicitly address pregnancy, breastfeeding, pineapple allergies, anticoagulant use, interactions with prescription medications, or the duplication of zinc.
  • The general claims regarding immune, allergy, inflammation, and cardiovascular support exceed the strength of the existing human evidence specifically related to this formula.

What does not

  • The formula specifies the names and dosages of its main ingredients instead of relying on a proprietary blend.
  • A daily intake of 15 mg of zinc is below the adult tolerable upper limit of 40 mg, prior to considering additional zinc sources.
  • A similar lecithin-based quercetin phytosome has demonstrated in human pharmacokinetic studies an enhanced absorption compared to plain quercetin.
  • The manufacturer offers a local contact address, phone number, and online instructions for taking two capsules daily with food.

Who is it for

This product is designed for adults seeking a multi-ingredient quercetin supplement, rather than plain quercetin alone. It emphasizes transparency by providing the specific daily amounts of zinc, vitamin C, bromelain, ginger, and citrus bioflavonoids. It is most suitable for individuals using this supplement as a complementary addition to their regular nutrition, not as a primary treatment. Users should consult with a healthcare professional or pharmacist to ensure it is appropriate for their medications and health history. The 180-capsule bottle offers a 90-day supply when taking the recommended two capsules per day.

Who is it not for

This product is not recommended for pregnant or breastfeeding individuals, children, those with kidney disease, or anyone managing cancer or a complex chronic condition without medical supervision. Individuals taking prescription medications—particularly anticoagulants, antiplatelet drugs, blood pressure medications, statins, antivirals, or tamsulosin—should exercise caution, as quercetin can influence drug metabolism and effects. People with a pineapple allergy should avoid it due to the presence of bromelain. Additionally, it may not be suitable for those who require independently verified potency and contaminant testing.

ASquared Nutrition Quercetin 1000mg with Zinc
#9

ASquared Nutrition Quercetin 1000mg with Zinc

Buyer Score 78/100 Integrity Score 72/100 ASquared Nutrition

Overview

The most notable health-positive aspect is the product's transparency. The label clearly indicates the daily amounts of all three active ingredients, along with specific instructions and precautions. It also highlights that the product is vegan, uses vegetable capsules, contains no preservatives, and is manufactured in the United States. The 30 mg zinc dose per serving is below the adult upper limit of 40 mg daily, but it provides limited flexibility for additional zinc intake from multivitamins, fortified foods, or other immune support products. The manufacturer claims that the formula is tested at an ISO 17025-accredited facility. However, publicly available information does not include batch certificates, detailed test methods, laboratory identification, or current independent certification for the finished product. No relevant FDA recall or warning letters were found in the records searched. Packaging details are minimal, merely instructing consumers to "Please recycle." The packaging material, recycled content, and local recycling guidelines are not specified, making it difficult to determine the environmental impact of disposal.

What works

  • There was no publicly available lot-specific assay or certificate of analysis to verify the identity, potency, heavy metal content, microbial safety, or capsule release of the finished product.
  • The manufacturer states that the facility is ISO 17025 accredited and has GMP certification, but does not specify the testing laboratory or offer a publicly accessible product certification.
  • A 1,000 mg dose of quercetin did not demonstrate a significant immune benefit in the general population during a large 12-week study, even though it is marketed for overall immunity and allergy relief.
  • Quercetin may affect how drugs are processed in the body, and a 30 mg dose of zinc can significantly increase zinc intake from food or other supplements. The label advises users to consult a healthcare professional but does not specify any particular drug categories or instructions regarding the timing of zinc intake.

What does not

  • Each of the three active ingredients has its specific daily amount disclosed separately, with no proprietary blend included.
  • The label provides highly detailed precautions for adult use, such as recommending medication reviews, avoiding kidney stones, and excluding use during pregnancy and breastfeeding.
  • The serving contains 30 mg of zinc, which is below the adult tolerable upper intake level of 40 mg per day. However, amounts from food and other supplements also contribute to this limit.
  • The label includes the company’s responsible name, U.S. mailing address, phone number, storage instructions, safety seal information, and an FDA disclaimer.

Who is it for

This product is ideal for adults seeking a capsule-based quercetin supplement with clearly disclosed amounts of quercetin, elderberry, and zinc, rather than a proprietary immune blend. It is most suitable for individuals who can monitor their overall zinc intake, have no history of kidney stones, are not pregnant or nursing, and are not taking medications without consulting a healthcare professional. The 60-capsule bottle is designed for a short-term, planned routine rather than an indefinite supplement regimen.

Who is it not for

This product is not recommended for children, pregnant or nursing women, or individuals with a history of kidney stones, as the label explicitly excludes or cautions these groups. Those taking prescription medications—especially drugs where absorption or metabolism is a concern—should avoid initiating use on their own, since quercetin can interact with certain human and laboratory tests, and zinc may interfere with some antibiotics and penicillamine. Additionally, it is not suitable for consumers who require publicly available batch testing, independent certification, or verified long-term safety at this daily quercetin dosage.

Micro Ingredients Quercetin Vitamin C Zinc Immune Support
#10

Micro Ingredients Quercetin Vitamin C Zinc Immune Support

Buyer Score 77/100 Integrity Score 68/100 Micro Ingredients

Overview

The formula clearly discloses its three main active ingredients, including the four forms of zinc, and does not contain a proprietary blend. The manufacturer states that each batch undergoes testing by third-party laboratories and that the product is non-GMO and free from soy, dairy, gluten, and tree nuts. However, these are manufacturer claims and are not supported by publicly available finished-product test results or independent certifications. A primary safety concern is the routine intake of 50 mg of zinc per serving, which exceeds the NIH recommended adult upper limit of 40 mg per day from all sources. Excess zinc can lead to a reduction in copper levels. Human studies also suggest that 500 mg of quercetin may influence drug-metabolizing enzymes. No FDA recall or warning letter specific to this product was found during public searches. While the flexible pouch may help reduce shipping volume, information about its material composition, recycled content, recyclability, and disposal instructions is not clearly provided.

What works

  • Consuming 50 mg of zinc daily exceeds the adult upper intake limit of 40 mg, prior to including zinc obtained from food or other supplements.
  • The label's general warning about medication and pregnancy does not specify any potential interactions with quercetin or the limitations related to high zinc intake.
  • There was no publicly available finished product testing data for quercetin regarding its identity, potency, heavy metals, microbes, or contaminants.
  • No publicly available certifications such as USP, NSF, Informed Choice, or any equivalent independent certification for finished products were found.
  • The listing does not specify the hydration state of quercetin nor does it include data on finished-capsule disintegration or dissolution.

What does not

  • The quantities of active ingredients and zinc types are listed separately, with no proprietary blends included.
  • A daily dose of 500 mg of quercetin has been used in human clinical studies, although not specifically to validate this particular product.
  • The pouch provides 120 labeled servings per day when using the recommended two capsules.
  • The list of exclusions for the manufacturer and retailer includes soy, dairy, gluten, and tree nuts.

Who is it for

This product is designed for adults seeking a long-lasting, clearly measured combination of quercetin, vitamin C, and zinc. It is ideal for individuals who have assessed their total zinc intake from food, multivitamins, cold remedies, and other supplements. The product is more suitable for a short-term, clinician-recommended supplement regimen rather than an ongoing wellness routine. Buyers should be comfortable with gelatin capsules and packaging in pouches instead of bottles. The 120-serving size is suitable for those who prefer not to reorder every month.

Who is it not for

This product is not ideal for individuals who are already taking zinc-containing multivitamins, lozenges, denture adhesives, or immune support products, as the labeled 50 mg of zinc exceeds the recommended upper intake level for adults. Pregnant or breastfeeding women, those managing kidney disease, undergoing cancer treatment, or taking prescription medications should consult a healthcare professional or pharmacist for personalized advice before use. Additionally, quercetin may affect drug-metabolizing enzymes, and zinc could interfere with certain medication schedules. It is also not suitable for children or individuals who avoid gelatin.