Most women take between 500 mg and 1,000 mg of quercetin per day, typically split into two doses. That range covers the majority of clinical research and aligns with what the FDA considers generally safe for healthy adults. There’s no official recommended daily allowance for quercetin, and no research has established a different optimal dose specifically for women versus men, so the general adult guidelines apply.
The Standard Daily Range
A common supplemental dose is 500 mg taken twice a day, totaling 1,000 mg. Many people also use a single 500 mg dose daily, especially for general antioxidant or immune support. Clinical trials have tested both 500 mg and 1,000 mg daily for up to 12 weeks with good tolerability in most participants.
The threshold that seems to matter most in research is 500 mg per day. A meta-analysis of seven randomized controlled trials found that quercetin significantly reduced C-reactive protein (a key marker of inflammation in the blood) at doses of 500 mg or higher, but not at lower doses. If you’re taking quercetin specifically for inflammatory support, staying at or above 500 mg daily appears to be the effective floor.
Doses Used in Women’s Health Research
For polycystic ovary syndrome (PCOS), one of the few conditions studied specifically in women, clinical trials have used either 500 mg or 1,000 mg daily for 12 weeks. These studies looked at hormonal and metabolic markers relevant to PCOS, and both doses showed benefits in the published research. If you’re considering quercetin for PCOS or related metabolic concerns, those are the doses with actual human data behind them.
For seasonal allergies, another popular reason people reach for quercetin, the commonly studied dose is 500 mg twice daily. Quercetin acts as a natural stabilizer for the immune cells that release histamine, which is why it’s marketed for allergy relief. That said, no optimal dose has been formally established for any single condition.
Side Effects at Higher Doses
Quercetin at typical supplemental doses is well tolerated by most people. The FDA classifies it as generally recognized as safe. Problems tend to show up at the higher end of the range or with prolonged use: people taking 1,000 mg daily over long periods have reported headaches, nausea, and tingling in the hands or feet.
There is also some evidence linking high doses to kidney damage, including lesions on the kidneys. The exact threshold for “high” isn’t precisely defined, but staying within the 500 to 1,000 mg range and not exceeding 1,000 mg daily without medical guidance is a reasonable precaution. If you have existing kidney issues, this is especially worth discussing with a provider before starting.
One Drug Interaction to Know About
Quercetin has a known moderate interaction with warfarin, a blood-thinning medication. Quercetin can affect how the body processes warfarin, potentially increasing the risk of bleeding. If you take warfarin or another anticoagulant, this is a combination to flag with your prescriber. Beyond warfarin, quercetin’s documented drug interactions are limited, but it can influence how certain enzymes in the liver metabolize medications, so mention it if you’re on other prescriptions.
Pregnancy and Breastfeeding
There is very little human safety data on quercetin supplementation during pregnancy or breastfeeding. The quercetin you get naturally through food is not a concern, but the concentrated amounts found in supplements (often 10 to 20 times what you’d get from diet alone) haven’t been adequately studied in pregnant or nursing women. Most clinical guidelines default to caution here, meaning supplemental quercetin is generally not recommended during pregnancy or lactation without specific medical advice.
What You Get From Food Alone
Quercetin is found in onions, apples, berries, grapes, broccoli, and tea. The amounts, though, are far lower than what supplements deliver. Onions contain roughly 28 to 49 mg per 100 grams, while apples provide only about 2 to 7 mg per 100 grams. You’d need to eat several cups of raw onions daily to approach even a 500 mg supplemental dose. Food sources contribute meaningful quercetin to your overall diet, but if you’re aiming for the doses used in clinical research, supplements are the practical route.
One thing worth noting: quercetin from onions is absorbed more efficiently than quercetin from many other sources, because of the specific chemical forms onions contain. Your body doesn’t absorb quercetin particularly well on its own, which is why many supplements pair it with vitamin C or bromelain (a compound from pineapple) to improve uptake.
How to Choose a Dose
For general wellness and antioxidant support, 500 mg once daily is a reasonable starting point. For targeted goals like reducing inflammation or managing allergy symptoms, 500 mg twice daily (1,000 mg total) is the dose most commonly supported by clinical trials. Starting lower and increasing after a week or two lets you gauge how your body responds.
Take quercetin with a meal that contains some fat, since it’s fat-soluble and absorbs better that way. Most studies have used supplementation periods of 8 to 12 weeks, so it’s not a compound where you’d expect immediate results. If you notice headaches or stomach discomfort, dropping back to 500 mg daily or splitting doses more evenly through the day often helps.