Quercetin
3,3',4',5,7-pentahydroxyflavone
Supplements. Modern nutrition.
Also called Bioflavonoid, Flavonol
Pinyin: hú pí sù
Spanish: Quercetina
May lower blood pressureA plant pigment found in onions, apples and berries, sold as a supplement for allergy and blood pressure claims.
Did you know? Onions are among the richest food sources of quercetin, one of the most common plant pigments in the diet.
What it may help, and how strong the proof is
- Blood pressure. Some small trials show a modest drop in blood pressure, often at doses of 500 mg a day or more. Results are mixed.Early proof
- Allergies. Small trials of quercetin for hay fever and allergy symptoms show mixed results. Lab studies suggest it may calm allergy cells, but human proof is limited.Early proof
Parts of the body
Traditional use
Quercetin has no traditional herbal use as a compound. People have eaten onions, apples and berries, its main food sources, for generations.
How it is classified
- Herbal actions
- Antioxidant, Anti-inflammatory. Energy: neutral.
How people take it
Studies commonly used 500 to 1,000 mg a day, often split into two doses. Food amounts are much smaller, so eating onions and apples is a gentler option.
Capsule and food.
Where to get it
Onions, apples, berries, kale and capers are good food sources. Supplements come as capsules, sometimes combined with bromelain or vitamin C, sold in stores and online.
Be careful
Quercetin is generally well tolerated, though high doses can cause headache, tingling or upset stomach. It may lower blood pressure and may affect blood clotting, so check with a doctor if you take BP medicine or blood thinners. Pregnancy data are limited, so avoid it unless a doctor says otherwise.
Avoid if: pregnancy; low blood pressure.
Mixing with other things
- Works well together
Some allergy and joint blends combine quercetin with bromelain, an enzyme from pineapple.
- Use cautionBlood pressure medicine (lisinopril, amlodipine, losartan)
May lower blood pressure a little, so BP medicines may need a check.
- Worth knowingBlood thinners (warfarin, Eliquis, Xarelto, Plavix, daily aspirin)
Lab studies suggest it may slow clotting. Combine with care.
Adds up with others that may lower blood pressure: , , , , , , , , , , , , , and 12 more.
The honest take
Quercetin is widely eaten and is safe in food amounts. Supplement trials are small, short and mixed, so claims about allergy and blood pressure are early. Claims that it fights viruses or cancer in people are not proven.