Quercetin

Quercetin

Quercetin is a flavonol, which is a class of flavonoids ^[1]. It is a nonessential nutrient.

Foods High in Quercetin

Quercetin naturally occurs in onions, red wine, Ginkgo biloba, green tea, buckwheat tea.

Quercetin Supplements

Quercetin supplements without prescription (over-the-counter) are available.

Quercetin Health Benefits

Quercetin supplements are POSSIBLY EFFECTIVE in reducing pain in prostate inflammation (chronic prostatitis) ^[2,3] and in lowering triglyceride levels ^[8].

There is INSUFFICIENT EVIDENCE ^[2] about the effectiveness of quercetin supplements in the prevention or treatment of asthma, atherosclerosis (artery hardening), cancer (lung, ovarian, pancreatic), cataracts, chronic fatigue syndrome, diabetes mellitus type 2, gastric or duodenal ulcers, gout, hay fever, heart disease, high cholesterol ^[8], high blood pressure, inflammation ^[5], pain and swelling, schizophrenia and viral infections, or in improving exercise performance ^[4,6] or in kidney transplantation.

Quercetin Safety: Toxicity, Side Effects

Quercetin supplements are POSSIBLY SAFE for most people when taken in appropriate amounts by mouth or as intravenous injections short-term (up to 12 weeks) ^[2].

Side effects may include nausea, headache and tingling ^[2]. Very high doses may cause kidney damage ^[2].

Not enough is known about the safety of quercetin supplements during pregnancy and breastfeeding, so women in these periods should avoid them ^[2].

Quercetin-Drug Interactions

Quercetin supplements may increase the effect of amiodarone, amitriptyline, clarithromycin, codeine, cyclosporin, diclofenac, fentanyl, glipizide, haloperidol, ibuprofen, imipramine, losartan, lovastatin, metoprolol, omeprazole, ondansetron, paclitaxel, paroxetine, phenytoin, piroxicam, propranolol, risperidone, rosiglitazone, sertraline, tamoxifen, tolbutamide, torsemide, tramadol, venlafaxine, verapamil, warfarin and others ^[2].