When to take Quercetin | PlanYourVitamins.com

What is quercetin good for?

Short answer: Quercetin has potential benefits for antioxidants, inflammation, cancer prevention, brain health, blood pressure and cardiovascular health.

Quercetin is a type of pigment, also known as a flavonoid, that is found naturally in many fruits and vegetables such as apples, onions, berries and green tea. The word flavonoid is actually derived from the latin "flavus", meaning yellow, and it is actually these flavonoids that are responsible for the petal coloration in flowers, for example.

Quercetin is known for its potent antioxidant and anti-inflammatory properties, and is thought to play a role in fighting cancer, regulating blood sugar, and helping in the prevention of cardiovascular diseases.

Benefits for cardiovasclular health

Studies show that quercetin protects heart health by promoting healthy blood vessel function, which in turn reduces the risk of heart disease drivers such as atherosclerosis or high blood pressure.

Several in vitro studies found that quercetin has a relaxing effect on blood vessels, and one animal study in mice found that daily supplementation of quercetin for five weeks resulted in a reduction in their systolic and diastolic blood pressure values by an average of 18% and 23% respectively.

Human studies involving daily supplementation of at least 500mg of quercetin showed similar results.

Role in cancer prevention

Quercetin has also demonstrated potent natural anticancer properties, and has been found to suppress cancer cell growth as well as induce cancer cell death in several studies involving a variety of different types of cancer.

Role in brain health

It is also thought that quercetin's antioxidant properties could protect against neurodegenerative conditions, such as Alzheimer's disease, with several animal studies showing that a quercetin rich diet and quercetin supplementation both resulted in reduced markers of Alzheimer's disease, along with improved cognitive function.

Allergy suppression & relief

Quercetin's anti-inflammatory effects could also help provide relief from allergy symptoms. Several in vitro and animal studies revealed that quercetin can block certain enzymes and chemicals that are responsible for allergy-related inflammation, such as histamine, meaning that quercetin can serve quite literally as a natural antihistamine.

One study in mice even demonstrated how quercetin supplementation suppressed peanut-related anaphylactic reactions.

When should I take quercetin?

Short answer: Quercetin is best taken with a meal, at any time of day, preferably including fatty foods (fish, meat, eggs, dairy, avocado, olive oil, nuts, seeds).

Taking quercetin on an empty stomach can increase the risk of potential side effects, such as nausea or stomach upset, therefore it is recommended to take quercetin together with a meal, ideally one that incorporates dietary fat, in order to maximize absorption.

What does quercetin combine well with?

Short answer: Quercetin has been shown to work well together with bromelain, curcumin, piperine, resveratrol, vitamin C, vitamin D and black pepper.

Quercetin with bromelain, piperine or vitamin C, for increased absorption

Unfortunately, despite its many benefits, quercetin on its own has low bioavailability, which means that your body has a rather hard time absorbing it. For this reason, you will often see formulations of quercetin that contain other compounds which are designed to enhance you body's ability to absorb it.

For example, quercetin combined with the enzyme bromelain, which is found in pineapples, is one such popular mix, as bromelain is known to significantly improve quercetin's bioavailability, as is piperine, the active ingredient in black pepper. Vitamin C is also known to enhance quercetin absorption.

Quercetin with resveratrol & curcumin, for antioxidant and anticancer activity

Research indicates that when quercetin is combined with other flavonoids, such as resveratrol, it has a synergistic effect. Furthermore, one study that involved a combination of quercetin, resveratrol and also curcumin revealed that this specific combination exhibited very potent anticancer properties through a number of cellular mechanisms.

Quercetin with vitamin D, for anticancer activity

It has also been found that a combination of quercetin and vitamin D3 shows strong additive effects in terms of preventing the spread of cancerous cells in breast cancer, compared to when the supplements were taken separately.

What are natural sources of quercetin?

If you are interested in achieving your daily quercetin intake through your diet, rich sources of quercetin include:

Capers
Apples
Onions
Bell peppers
Kale
Asparagus
Tomatos
Cherries
Broccoli

Quercetin data sources & further reading

Last updated by Asklepios on 30th January, 2025