Dr. Vliet’s Health Tip: Quercetin Revolution: Breakthroughs in Absorption Technology Unleash This Powerhouse!

Quercetin’s Health Benefits include:

1. Fighting free radicals
2. Reducing inflammation
3. Reducing cancer risk
4. Reducing the risk of neurological diseases
5. Reducing the risk of infections
6. Reducing the risk of heart disease
7. Lowering blood pressure
8. Relieving allergies and respiratory challenges

Quercetin is actually one of the most common and well-researched micronutrients in the flavonoid class of polyphenols, but in the past, has been just a niche nutrient beloved by nutrition enthusiasts because it was so difficult for our bodies to absorb quercetin in its natural form in onions, apples, citrus fruits, berries, cruciferous vegetables, nuts, wine, black and green tea, and is also ginkgo biloba, a popular medicinal plant.

Major new breakthroughs in technology, however, have led to enormous improvements in quercetin absorption and bioavailability.  As a result, it now commands serious attention from researchers exploring its potential for heart, immune, brain, and even women’s health.  My article today explores the latest breakthroughs in quercetin research—how innovative delivery systems are transforming its bioavailability, what the newest clinical trials reveal, and how to make smart, evidence-based decisions about supplementation.

The great news is that our Truth for Health Foundation Quercetin supplement TruQuercetin™ 20X Plus, an Advanced Delivery Phytosome Quercetin makes use of these revolutionary improvements in absorption and bioavailability.  I will describe more about this shortly, after reviewing some of the new absorption technologies and how they work to maximize quercetin’s health impact.

Clinical Evidence: Where Quercetin is Making a Difference
Recent clinical trials and reviews highlight several key areas where quercetin supplementation is showing great promise:

1. Cardiometabolic and Vascular Health: Across 17 randomized trials, quercetin (mainly 500 mg/day, 2–12 weeks) was found to significantly lowered both systolic and diastolic blood pressure and improved HDL (“good” cholesterol) and triglycerides, especially in studies lasting eight weeks or more. There’s also evidence of improved endothelial (blood vessel lining) function and protection against cholesterol-related vascular damage.
2. Immune Support and Post-Viral Recovery: In several open-label randomized trials, early supplementation with 500 mg quercetin daily for about two weeks in COVID-19 outpatients sped up viral clearance and symptom resolution compared to usual care. This is quite significant and cost effective! Combination trials are now underway for “Long COVID,” testing quercetin with curcumin for symptom reduction and improved quality of life.
3. Neuroprotection and Brain Health: Preclinical and early human studies suggest quercetin with advanced delivery systems – as discussed below and found in TruQuercetin™ 20X Plus—can reduce oxidative stress and inflammation in brain tissue, with potential to support microvascular health. We still need large, high-quality cognitive trials in humans to confirm these benefits.
4. Women’s Health: Ongoing research is exploring quercetin’s role in endometriosis and other hormone-related conditions. Early data suggest benefits may relate to its anti-inflammatory and antioxidant effects, but clinical research is still preliminary.

The Science Behind Quercetin: How It Works in the Body

Quercetin’s appeal lies in its versatile mechanisms of action. It acts as a broad-spectrum anti-inflammatory and antioxidant, helping to balance the body’s immune responses and protect against oxidative stress, the major driver of aging and chronic illness.

Recent studies show how quercetin does this:

1. Modulates key cell signaling pathways (like NF-κB, Nrf2, AMPK/SIRT1) which reduces the production of inflammatory substances and boosts the body’s own antioxidant enzymes.
2. Supports blood vessel health by lowering oxidative stress, inhibiting the oxidation of LDL (“bad”) cholesterol, and calming cellular messengers that trigger vascular inflammation. These effects translate meaningful improvements in blood pressure and cholesterol in clinical studies.
3. Protects heart muscle and mitochondria (the energy production organelles in every cell of our body!) in models of heart injury, reducing cell death and tissue damage via improved cellular “survival” pathways.
4. Brain health benefits now possible with advanced delivery systems allowing quercetin to counteract oxidative stress and inflammation in models of neurodegenerative diseases and early-life stress.

Bioavailability: The Main Hurdle in Quercetin Supplementation
Despite its impressive actions in the lab, quercetin’s greatest challenge is bioavailability—how much actually gets into your bloodstream after you take it. Unformulated quercetin (aglycone) is poorly absorbed and rapidly eliminated, with only a small fraction reaching target tissues.

Quercetin’s poor absorption spurred a wave of research into new ways of making quercetin more “body friendly” and available to be used body tissues. These new delivery technologies are dramatically improving quercetin’s absorption and action.

Some of the leading approaches include:

• Lecithin-Based Phytosome: Quercetin molecules are combined with phospholipids (usually from sunflower or soy lecithin), creating a “phytosome” complex that mimics cell membranes. This boosts solubility, aids in lymphatic (fat-based) absorption, and delivers quercetin more efficiently. Human studies show phytosome quercetin can achieve 18–20 times higher blood levels than the same dose of plain quercetin. 

In fact, a clinical study evaluating the absorption of Quercetin Phytosome compared to unformulated quercetin was approximately 20-fold higher and hence the name of our product: TruQuercetin™ 20X Plus.

• Self-Emulsifying Galactomannan Systems: this technique blends quercetin with natural fibers (like fenugreek galactomannan) and lecithin to create tiny droplets (micelles) in the gut that “emulsify” to boost bioavailability as much as 62-fold in some studies.  These are newer options and less widely available than phytosome products.
• Cyclodextrin Complexes: Quercetin is “caged” by cyclodextrin molecules that improve water solubility and stability. Human data show about an 11-fold increase in absorption, making this an attractive option for functional foods and drinks.
• Liposomes and Nano formulations: Encapsulating quercetin in nanoscale lipid bubbles or other particles enhances stability, controlled release, and absorption—up to ninefold increases in preclinical studies. Most of these liposomal and nano formulations remain in the research or specialty product stage at this time.

Of all these new approaches, lecithin-based phytosome quercetin (as found in our TruQuercetin™ 20X Plus) stands out as the most clinically validated, commercially available option for maximizing systemic exposure and supplement reliability.

Dose equivalence for safe and effective supplementation:

Bioavailability varies so much between these various formulations, it is critical to understand how to figure dose equivalence in order to supplement safely with quercetin.   Pharmacokinetic (PK) data show:

1. 250 mg quercetin phytosome ≈ 1–1.25 grams of unformulated quercetin1.
2. 500 mg quercetin phytosome ≈ 2–2.5 grams of unformulated quercetin

This means that the typical 500 mg/day phytosome dose used in clinical studies delivers the same or greater systemic exposure as much higher plain quercetin doses—without the need for mega-dosing. For most adults, 150–1000 mg/day (especially in enhanced forms) for 4–12 weeks is the range supported by human trials, with emerging guidance favoring formulated versions for targeted systemic or brain effects.

To determine how much quercetin gets into circulation, researchers use pharmacokinetic studies in healthy volunteers. Participants take single oral doses of both unformulated and formulated quercetin (like phytosome) under controlled conditions, and have their blood drawn at regular intervals over 24 hours. Quercetin and its metabolites are measured using sophisticated lab methods (HPLC–MS/MS or UPLC–MS/MS), which can distinguish between “free” (unconjugated) quercetin and forms processed by the body.

The key parameters are:

1. Cmax: The peak plasma concentration (how high the level gets in your blood).
2. AUC (“Area Under the Curve”): Represents the total quercetin exposure over time.

Improved bioavailability is defined by higher Cmax and AUC when the same dose is given in an enhanced formulation. For phytosome, studies report about 18–20 times higher values for both, compared to regular quercetin.

When selecting a quercetin supplement, consider the following:

1. Lecithin-based phytosome quercetin currently offers the most robust human data for absorption and efficacy, with known safety profiles and widely available commercial products.
2. Match the formulation to your health goals: If you’re targeting systemic (whole-body) or brain effects, enhanced forms like phytosome will be necessary to achieve your goals.
3. For general antioxidant support, standard quercetin may work, but you will need higher doses, which may have more side effects and also cost more to get what you need than if you used a high quality  enhanced bio-available phytosome quercetin.

TruQuercetin 20X Plus an Advanced Delivery Phytosome Quercetin

Quercetin Phytosome technology works by connecting botanicals like quercetin with phospholipids to improve solubility and enhance absorption and bioavailability by the body, which is important for efficacy. In fact, a clinical study evaluating the absorption of Quercetin Phytosome compared to unformulated quercetin was approximately 20-fold higher and hence the name TruQuercetin™ 20X Plus.

The “Plus” in TruQuercetin™ 20X Plus: Synergistic Supplements to Maximize Quercetin’s Benefits

TruQuercetin™ 20X Plus provides a complex of active ingredients that work together synergistically to help the body balance immune-related responses, oxidative stress levels, and the associated respiratory symptoms.
TruQuercetin™ 20X Plus is unique due to the powerful combination of highly available quercetin with the complementary actions of NAC, Nettle extract and Vitamin C. This combination has been found to be extremely helpful in combating viral infections, including those we experienced with SARS CoV2 and may experience from similar threats.

The respiratory-immune benefits of Quercetin Phytosome were studied in Japanese adults with eye and nose discomfort using rhino conjunctivitis quality of life questionnaire scores and other tests. Over the course of 4 weeks, those consuming 200 mg/d of Quercetin Phytosome experienced signifcant subjective improvements in sleep and severity of symptoms, such as sneezing, ocular itching, and runny nose, compared with the placebo group.

Another study also demonstrated the benefits of Quercetin Phytosome in individuals with early-stage respiratory illness. In addition to standard care, subjects taking doses of 500 to 1500 mg/d of Quercetin Phytosome demonstrated better clearance, improved resolution of acute symptoms, reduced illness progression, and reduced serum inflammatory biomarker levels compared with those receiving standard care alone.

1. N-Acetyl-L-Cysteine (NAC)

Oxidative stress and the interrelated production of inflammatory cytokines are thought to play a significant role in propagating respiratory symptoms in immune-reactive pathways. NAC has direct antioxidant activities and is a precursor to glutathione biosynthesis which is helpful in addressing the low glutathione levels associated with oxidative stress and implicated in immune dysregulation. It is thought that replenishing antioxidants may be critical in normalizing immune function and may prove beneficial in the treatment and prevention of SARS-Cov-2.

NAC is also a mucolytic agent that decreases mucus viscosity and facilitates its clearance. And for those with environmental hypersensitivity, an animal model showed that NAC reduced lung oxidative stress, improved lung glutathione status, reduced inflammatory transcription factor activity, and decreased airway hyperresponsiveness.

1. Nettle Extract (Urtica dioica and/or Urtica urens)

Nettles have been used as a natural remedy for 2,000 years.  Modern scientists have been working to validate its historical use and elucidate mechanisms of action. Nettle leaves provide many active components, such as flavonoids, phenolic compounds, organic acids, and vitamins, as well as volatile compounds like fatty acids and polysaccharides.

In vitro testing demonstrated that an extract of nettle leaves inhibited the following: histamine-1 receptors; tryptase, which influences mast cell degranulation; prostaglandin D2 production; and COX1 and COX2 activity. In a double-blind, randomized study, subjects (n = 69) were given 300-mg capsules of freeze-dried nettle or placebo and instructed to take 2 capsules at the onset of seasonal allergy symptoms and then ad libitum. The daily dose ranged from 1 to 7, with a mean of 2.8 doses (300 mg per dose). Overall, 58% of subjects rated nettle moderately effective or better compared with only 37% for placebo.

1. Vitamin C

Vitamin C is an antioxidant that helps scavenge free radicals from oxidative stress, has essential roles in immune system function and assists in quercetin recycling. The coadministration of quercetin and vitamin C imparts complementary immunomodulatory effects.

In addition, we know that oxidative stress contributes to negative biological impacts on airways, and it has been observed that low vitamin C levels have been found in environmentally hypersensitive individuals and those facing other respiratory challenges.

In summary: Our TruQuercetin™ 20X Plus is a unique complex that combines research-based technology with traditional antioxidant ingredients to confer optimal health benefits. The components of TruQuercetin 20X Plus were selected to work synergistically for optimal relief of respiratory system challenges, and robustly support the respiratory system and its organs, including nasal passages, through complementary mechanisms of action.

The foundation for smart quercetin supplementation is now stronger than ever. Choose formulations wisely, consider synergistic partners like vitamin C.  Look for products supported by rigorous pharmacokinetic and clinical data such as found in TruQuercetin™ 20X Plus.

Recent advances have transformed quercetin from a promising but underperforming supplement to a bioavailable, evidence-backed option for heart, immune, brain, women’s health and respiratory health. The emergence of phytosome and other advanced delivery systems marks a turning point, allowing therapeutic benefits at lower, safer doses. As the science continues to evolve, quercetin’s star will continue to rise in the world of health and nutrition.

CAUTION: As always, we urge you to avoid supplements without checking knowledgeable sources to evaluate your medical situation, proper lab tests to verify what is needed, and to make sure to avoid adverse interactions with prescription medicines and other supplements you take.

All Truth for Health Foundation Products Meet or Exceed cGMP Quality Standards, the highest quality standard for supplements sold in the USA.
For more information, references from studies are listed in the Product Data Sheets for each product, available on our website.  Under medical practice regulations, we are unable to answer individual medical sdquestions or make specific individual supplement recommendations for people who are not established patients of Dr. Vliet’s independent medical practice.

I encourage you to consider our other natural medicines with our top quality, cGMP-compliant professional formulas for TruImmune™Boost, TruNAC™, TruImmunoglobulin,™ TruC with BioFlav™ (Vitamin C with complete Bioflavonoids), Tru BioD3™, TruZinc™, TruMitochondrial ™Boost and TruProBiotic™ Daily to replenish critical bifidobacteria depleted by COVID shots, viral illnesses, and antibiotic therapy.

To Your good health and improving resilience!
Elizabeth Lee Vliet, MD

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