Quercetin: A Supercharged Anti-Inflammatory, Anti-viral, Senolytic, and more – ALIVE BY SCIENCE – Bioavailable NAD+ Boosters

Quercetin: A Supercharged Anti-Inflammatory, Anti-viral, Senolytic, and more


What is Quercetin?

The name quercetin comes from the Latin word “Quercetum” which means Oak Forest, belongs to the class called flavonols that cannot be produced in the human body. (Source)

Quercetin is said to be one of the most widely used bioflavonoids for the treatment of metabolic and inflammatory disorders, however, poor aqueous solubility, chemical instability, and low oral bioavailability significantly limits its applications.  (Source)


Potent Anti-Inflammatory, Anti-viral, and Senolytic

Quercetin is a powerhouse immunomodulator shown to fortify immune function and neutralize free radicals in the body to support a tempered inflammatory response.

It has the unique ability to act directly on cells as an anti-inflammatory agent and has properties demonstrated in vivo and in vitro consistent with protection against cardiovascular disease.  (Source)

“Quercetin has strong antioxidant, anti-inflammatory, immunomodulatory, and antiviral properties, and it is characterized by a very high safety profile, exerted in animals and in humans.” (Source)

However, the bioavailability of quercetin is extremely low and its absorption can be affected by macronutrients.  (Source)


Absorption Severely Limited by Water Insolubility

Quercetin digested in the human body (e.g., mouth, small intestine, liver, kidneys) suffers glucuronidation, sulfation, or methylation.

On its own, quercetin’s limited absorption inhibits it from penetrating the cell membrane into the interior of the cell.  (Source)

“Quercetin, because of its basic chemical structure, shows prominent antioxidant activity which possibly assists it to reduce free radicals from establishing resonance-stabilized phenoxyl radicals.

Quercetin has a low absorption rate in the gastrointestinal tract and under the Biopharmaceutics Classification System, it is classified as a class IV compound (low solubility, low permeability).

It is believed that low bioavailability of crystalline quercetin as a pure substance is the result of its low solubility in the digestive tract.

In addition, the bioavailability of quercetin can be affected by food.  (Source)

To overcome these issues, nanoencapsulation of quercetin is performed which could significantly improve its stability, efficacy, and bioavailability.”  (Source)


Liposomal Quercetin Increases Oral Absorption 20x


To overcome this limitation, scientists developed liposomal quercetin to investigate its distribution in vivo.

Liposomes chauffeur active ingredients into the body via the gut and into your cells to be used.

A study published in June, 2021 showed promising results for liposomal quercetin for boosting immunity.

Quercetin in a delivery-food grade system with sunflower phospholipids increases its oral absorption up to 20-fold.”  (Source)

Liposomes can act as a suitable vesicle to enhance the solubility of hydrophobic bioactive compounds by encapsulating the compounds within the membrane bilayers.

Liposomal Quercetin provides sustained release

In vitro release experiments showed that the release rate of liposomal quercetin is much slower than that of free quercetin, and achieves a sustained release effect and improves the medicinal value of quercetin.  (Source)

“Based on in vitro characteristic results, we concluded that this nano-formulation was a stable nanoparticulate system with high quercetin loading.

After nano-encapsulation, compared with quercetin alone, much strong inhibition capabilities.”


This study found Liposomal Quercetin greatly suppressed the growth of solid tumors in mice and was much more effective than non-liposomal quercetin.

Researchers believe the increased effectiveness was due to increased bioavailability to cells.

The chart at right shows Liposomal Quercetin (Q-PEGL) was available in the plasma for 24 hours, vs 2 hours for standard Quercetin (FQ).

This is because Liposomes are composed of the same material as the cell membrane, so is not seen as a foriegn substance to be filtered out by the liver.


Our data indicated that peglyated liposomal quercetin can significantly improve the solubility and bioavailability of quercetin and can be a potential application in the treatment of tumor.” (Source)

Liposomes merge with cell membrane to deliver ingredients


Quercetin-loaded liposomes are able to penetrate the cell membrane bilayer, allowing the pure quercetin to be effectively ushered into the gut for ease of absorption.  (Source)


Liposomal Quercetin Promotes Immune Resilience

A 2021 study shows liposomal quercetin is an effective agent in combination with standard care, when used in early stage of viral infection. (Source)


Quercetin contributes to immune resilience through a few different pathways.  It has antiviral and anti-inflammatory properties to support the natural immune response.  (Source)

Quercetin Liposomes Have Very High Safety Profile

“Quercetin has strong antioxidant, anti-inflammatory, immunomodulatory, and antiviral properties, and it is characterized by a very high safety profile, exerted in animals and in humans.”  (Source)


Quercetin May Lower Inflammatory Biomarkers

Flavonoid quercetin is a semi-lipophilic molecule that is of great interest to researchers due to its nutritional value. This compound has been shown, in vitro, to be a strong antioxidant and is one of the most powerful scavengers of reactive oxygen species. The free radical-scavenging effect of quercetin is based on its ability to donate a proton.

Quercetin has been shown to reduce inflammatory pain via the inhibition of oxidative stress and cytokine production.  (Source)

One study published in the European Journal of Clinical Nutrition found that supplementing with quercetin helped lower levels of the inflammatory biomarker C-reactive protein (CRP).  (Source)

“Our findings showed a significant effect of quercetin supplementation on the C-reactive protein-especially at doses above 500 mg/day.”


Quercetin as a Natural Allergy Relief

Quercetin’s best-known mechanism of action involves its ability to stabilize mast cell membranes, which decreases the release of histamine into the cells—an inflammatory chemical involved in allergic symptoms such as sneezing and itching.  

In this way it provides nutritional support for individuals who occasionally suffer from allergies.

Quercetin has the unique ability to help block histamine release, the main trigger for respiratory and sinus health issues. (Source)

That’s why it’s a very popular phytonutrient for promoting respiratory health and sinus comfort.

“In conclusion, our results indicate that quercetin is more effective than cromolyn in inhibiting release of pro-inflammatory cytokines from human mast cells.”  (Source)

Quercetin Supports Optimal Blood Pressure and Cardiovascular Health

Quercetin also has impressive cardiovascular benefits: One meta‐analysis of randomized controlled trials found that supplementing with the plant powerhouse could help stabilize blood pressure.  (Source)

In a study done by Greek cardiologists on thirty men who already had coronary heart disease (CHD) on the consumption of red grape polyphenol extract rich in quercetin caused an increase in flow-mediated dilation of major arteries, a potent indicator of improved endothelial health. (Source)

Quercetin May Strengthen Blood Vessels

Quercetin may improve blood vessel cell health and blood flow through arteries in people with heart disease.  (Source)

According to a study by the American Heart and Stroke Association, taking quercetin supplements could be an effective way to reduce blood pressure.   (Source)

Other research showed that people who were overweight and took a quercetin supplement of 150 milligrams daily had lower levels of harmful cholesterol in their blood, as well as reduced systolic blood pressure, which measures the pressure in the blood vessels during a heartbeat.  (Source)


Endogenous and Exogenous Mediators of Quercetin Bioavailability

Towards an Understanding of the Low Bioavailability of Quercetin:  A Study of Its Interaction with Intestinal Lipids

Quercetin Reduces Systolic Blood Pressure and Plasma Oxidized Low-Density Lipoprotein Concentrations in Overweight Subjects with a High-Cardiovascular Disease Risk Phenotype:  A Double-blinded, Placebo-Controlled Cross-over Study

Quercetin Is More Effective than Cromolyn in Blocking Human Mast Cell Cytokine Release and Inhibits Contact Dermatitis and Photosensitivity in Humans

Overviews of Biological Importance of Quercetin: A Bioactive Flavonoid

Liposomal Quercetin Efficiently Suppresses Growth of Solid Tumors in Murine Models

Improved Therapeutic Efficacy of Quercetin-Loaded Polymeric Nanoparticles

Polyphenolic Compounds from Red Grapes Acutely Improve Endothelial Function in Patients with Coronary Heart Disease.

Review of the Biology of Quercetin and Related Bioflavonoids

Quercetin and Endurance Exercise Capacity

The Effects of Quercetin Supplementation on Body Composition, Exercise Performance and Muscle Damage in Athletes

Liposomes as Advanced Delivery Systems for Nutraceuticals

Effects of Quercetin on Blood Pressure: A Systematic Review and Meta‐Analysis of Randomized Controlled Trials

Quercetin, Inflammation and Immunity

Impact of Quercetin Encapsulation with Added Phytosterols on Bilayer Membrane and Photothermal-Alteration of Novel Mixed Soy Lecithin-Based Liposome

Quercetin-Loaded Nanomedicine as Nutritional Application

Quercetin:  Antiviral Significance and Possible COVID-19 Integrative Considerations