Other compounds

Quercetin

Also called: quercetin

A plant pigment in onions and apples.

Why people take it
Allergies, immunity.
What the evidence says
Limited evidence.
How it is usually taken
Usually 500 mg to 1 g a day.
Be careful
Interacts with some antibiotics and medicines; high doses may affect kidneys.
Medicines it can interact with
May raise levels of some medicines (ciclosporin) and reduce quinolone antibiotic effect.

Other other compounds

Alpha-lipoic acidResveratrolPterostilbeneNMNSpermidineFisetinPQQSulforaphaneDIMDHEAMelatoninCaffeine and L-theanineCannabidiol (CBD)Hemp seedBee pollenRoyal jellyPropolisManuka honeyChlorophyllWheatgrass

Common questions

What is Quercetin?

A plant pigment in onions and apples.

Why do people take Quercetin?

Allergies, immunity.

Does Quercetin work?

Limited evidence.

How much Quercetin do people take?

Usually 500 mg to 1 g a day.

Is Quercetin safe?

Interacts with some antibiotics and medicines; high doses may affect kidneys.

Does Quercetin interact with medicines?

May raise levels of some medicines (ciclosporin) and reduce quinolone antibiotic effect.

Sources and further reading

Last reviewed 31 October 2026. Written by Satya Babu.

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For information only, not medical advice. Supplements are not medicines: they are not tested and approved like drugs before they are sold, and they can interact with medicines. Talk to your doctor or pharmacist before you start one, especially if you are pregnant or breastfeeding, take regular medicines, or have kidney, liver or heart disease.