Quercetin

In the Quercetin collection we bring together food supplements with quercetin, alone or combined with bromelain, vitamin C, rutin, resveratrol and other polyphenols, from brands such as Thorne, NOW Foods, Solaray, Lamberts, Suravitasan, Zeinpharma, HOP Biologics, Hawa Pharma and Researched Nutritionals. You will find capsules and tablets with plain quercetin, quercetin phytosome and combined formulas.

What quercetin is

Quercetin is a flavonoid, one of the most common polyphenols in the plant kingdom. It is one of the pigments that give colour to many fruits and vegetables.

Where it is found in food

The richest sources are capers, red onion, apples with their skin, berries, tea and leafy greens. In a varied diet, daily intake is usually in the tens of milligrams, well below supplement doses.

Forms of quercetin

In food, quercetin is almost always bound to sugars, as in rutin and isoquercitrin. In supplements it appears as free quercetin (aglycone), which dissolves poorly in water, or in forms designed to make absorption easier, such as phytosome (quercetin bound to sunflower or soy phospholipids) and enzymatically modified quercetin. Rutin, also called rutoside, is quercetin bound to a sugar and is available as a separate supplement.

Types of products

Plain quercetin

Quercetin capsules with 250 to 600 mg per serving, as aglycone or phytosome. Compare the amount of quercetin per serving and the form stated on the label.

Quercetin with bromelain and vitamin C

This is one of the oldest combinations. Bromelain is an enzyme from pineapple and vitamin C completes the formula. Versions have different daily doses, so check how many capsules make up one serving.

Formulas with other polyphenols

Quercetin with resveratrol, curcumin, rutin or beta-glucans, and formulas with quercetin, MSM, minerals and plant extracts.

Precautions

• Quercetin may interfere with some medicines, such as certain antibiotics (quinolones), ciclosporin and medicines processed by the liver. If you take medication, talk to your doctor or pharmacist.
• Formulas with bromelain are not suitable for people allergic to pineapple or, without medical advice, for people taking anticoagulants.
• If you have kidney disease, seek advice before taking high doses of quercetin.
• During pregnancy and breastfeeding, ask a health professional for advice.

See also the Liver and Antioxidants collection.