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Quercetin Dehydrate

Also known as: Quercetin dihydrate, Quercetin hydrate, Quercetin, Quercetin Dihydrate

Overview

Quercetin dihydrate is a flavonoid, a type of polyphenolic plant compound, found in various fruits, vegetables, and grains like onions, apples, berries, and tea. As a dihydrate, it contains two water molecules, enhancing its stability and solubility compared to anhydrous quercetin. It is primarily used for its antioxidant, anti-inflammatory, and potential antiviral properties. Supplementation is often considered for cardiovascular health, immune support, and reducing oxidative stress. While quercetin dihydrate is more stable and soluble, its bioavailability remains limited without specific formulation strategies. Research on quercetin dihydrate is moderately to highly developed, with numerous randomized controlled trials and meta-analyses focusing on inflammatory markers, cardiovascular parameters, and viral infections. Evidence quality is generally good, though challenges related to bioavailability and variations in dosing and study populations persist.

Benefits

Quercetin dihydrate has demonstrated several evidence-based benefits. A meta-analysis of RCTs showed a significant reduction in COVID-19 severity, including decreased lactate dehydrogenase (LDH) activity, hospital admission risk, ICU admission, and mortality. Systematic reviews also indicate that quercetin supplementation can improve plasma lipid profiles by modestly lowering total and LDL cholesterol, as well as reducing systolic blood pressure, suggesting cardiovascular benefits. Furthermore, meta-analyses support its anti-inflammatory effects, showing that quercetin inhibits inflammatory cytokines and markers, which may contribute to systemic health and reduce chronic inflammation. Some studies suggest potential antidiabetic effects, antioxidant support, and immune modulation, though these findings are primarily from animal studies or smaller human trials. The benefits are most pronounced in individuals with viral infections, cardiovascular risk factors, and inflammatory conditions.

How it works

Quercetin dihydrate functions primarily as a potent antioxidant, scavenging free radicals and reducing oxidative stress. It modulates inflammatory pathways by inhibiting NF-κB and reducing the production of pro-inflammatory cytokines. Additionally, it may interfere with viral replication mechanisms. Quercetin impacts the immune system by regulating immune cell function, supports cardiovascular health by improving endothelial function, and influences metabolic pathways. Its molecular targets include enzymes like LDH, inflammatory cytokines such as TNF-α and IL-6, and signaling molecules involved in oxidative stress. While quercetin dihydrate is more soluble than anhydrous quercetin, its oral bioavailability remains low due to poor absorption and rapid metabolism. Co-administration with vitamin C or formulation as phytosomes may enhance its bioavailability.

Side effects

Quercetin dihydrate is generally recognized as safe when taken at typical supplemental doses. Common side effects, occurring in more than 5% of users, include mild gastrointestinal discomfort. Uncommon side effects, affecting 1-5% of users, may include headache and tingling sensations. Rare side effects, seen in less than 1% of users, may involve allergic reactions, though these are very rare. Quercetin may interact with anticoagulants and antiplatelet drugs due to its mild blood-thinning effects. Caution is advised for individuals on blood thinners or with known allergies to flavonoids. Due to limited data, pregnant or breastfeeding women should use it with caution. The EFSA panel has conducted risk assessments confirming its safety in food supplements at recommended dosages.

Dosage

The minimum effective dose of quercetin dihydrate is around 500 mg per day, with optimal dosage ranges typically between 500 and 1000 mg daily for anti-inflammatory and cardiovascular benefits. Doses up to 1000 mg daily are generally well-tolerated, but higher doses should be approached with caution. Dividing the daily dose and taking it with meals may improve absorption and reduce gastrointestinal side effects. The dihydrate form is preferred for its stability. Formulations designed to enhance bioavailability, such as liposomal quercetin, may improve efficacy. Co-administration with vitamin C or fats can also enhance absorption. While specific required cofactors are not definitively established, vitamin C and other antioxidants may synergize with quercetin's effects.

FAQs

Is quercetin dihydrate more effective than anhydrous quercetin?

Yes, quercetin dihydrate is generally considered more effective due to its increased stability and solubility, which can improve its absorption, although enhanced formulations are still recommended to maximize bioavailability.

Can quercetin dihydrate prevent or treat COVID-19?

Meta-analyses suggest that quercetin dihydrate may reduce the severity and mortality of COVID-19, but it should not replace standard medical care. It is best used as a supportive measure alongside conventional treatments.

How long does it take to see the effects of quercetin dihydrate?

Acute effects, such as those related to viral infections, may be noticeable within a few weeks. Cardiovascular benefits and improvements in inflammatory markers may require longer-term supplementation, typically several weeks to months.

Is it safe to take quercetin dihydrate daily?

Yes, quercetin dihydrate is generally safe to take daily at recommended doses, with minimal side effects reported. However, individuals on blood thinners should exercise caution due to potential interactions.

Research Sources

https://onlinelibrary.wiley.com/doi/10.1002/fsn3.3715 – This systematic review and meta-analysis included five RCTs with 544 COVID-19 patients. The study found that quercetin supplementation significantly reduced LDH activity, hospital and ICU admissions, and mortality, suggesting a potential benefit in managing COVID-19 severity. The results showed statistical significance despite moderate heterogeneity and variations in dosing regimens.
https://www.lifeextension.com/wellness/supplements/quercetin-dihydrate-vs-quercetin – This article discusses the differences between quercetin dihydrate and anhydrous quercetin, highlighting the improved stability and solubility of the dihydrate form. It emphasizes that while quercetin dihydrate is more stable, its bioavailability remains limited without enhanced formulations, such as liposomal delivery systems.
https://vkm.no/download/18.111b9bb51900c58335fcde26/1718703086649/Rapport%20quercetin_rutin_final_130624-komprimert.pdf – This report provides a comprehensive safety evaluation of quercetin dihydrate in supplements. The assessment concludes that quercetin dihydrate is safe at typical supplemental doses and poses a low risk of adverse effects, supporting its use as a dietary supplement.
https://academic.oup.com/nutritionreviews/article/78/8/615/5697189?login=false – This systematic review summarizes the effects of quercetin supplementation on lipid profiles and blood pressure. The review found modest but consistent reductions in total cholesterol and systolic blood pressure across multiple RCTs, indicating potential cardiovascular benefits. The study acknowledges variations in sample sizes and overall quality, with some heterogeneity noted.
https://www.healthline.com/nutrition/quercetin – This article provides a general overview of quercetin, discussing its sources, benefits, and potential uses. It highlights quercetin's antioxidant and anti-inflammatory properties and mentions its presence in various fruits and vegetables, making it a popular dietary supplement.