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Quercetin

Best studied for: Seasonal allergies; Chronic inflammation; Heart health. Most used for allergy relief, reducing inflammation, supporting heart health.

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What is q uercetin ? Quercetin is a flavonoid, a type of antioxidant commonly found in plants, fruits, and vegetables. It has gained attention for its potential health benefits, particularly in reducing inflammation and protecting against chronic diseases. How does it work? Quercetin has been shown to have various beneficial effects on human health, including its ability to reduce oxidative stress and inflammation, as well as its potential to prevent and treat certain chronic diseases. It is believed to work by inhibiting certain enzymes and pathways involved in inflammation and oxidative stress. What are the active ingredients that are important for its medicinal properties? Quercetin is the active ingredient responsible for its medicinal properties. What forms does it come in? Quercetin is available in supplement form, as well as in various foods such as onions, apples, berries, and tea. When was it first used for medicinal purposes? Quercetin has been used in traditional medicine for centuries, particularly in Asian cultures, to treat various ailments.

Helps

What does Quercetin help with? Quercetin is a natural plant pigment. You take it in food through onions, apples, capers, berries and tea. It is also sold on its own as a pill or capsule. Sore muscles and tiredness after hard exercise Strong evidence — a published meta-analysis of human exercise trials. A published meta-analysis found less muscle soreness and less felt fatigue after intense exercise. Gains in endurance were modest, not large. The trial sizes and doses behind that analysis are not on file here. Evidence grade A · Traditional tier T0 High blood pressure Good evidence — several clinical trials in people. Several clinical trials found lower top and bottom blood pressure numbers. The change was clearest in people whose readings were already high. In those trials it appeared to relax and widen blood vessels, so the heart pumped against less resistance. Evidence grade B · Traditional tier T0 Long-term prostate pain and pelvic pain in men Good evidence — one published clinical trial in men with non-bacterial chronic prostatitis. One published clinical trial enrolled men with long-term prostate pain not caused by bacteria. The men who took quercetin had better pain scores and better quality-of-life scores. The trial size and the dose used are not on file here. Evidence grade B · Traditional tier T0 Ongoing low-grade inflammation Early evidence — human studies of blood markers, sizes and doses not on file. In human studies, taking it regularly lowered markers of inflammation in the blood. Lab work shows it turns down some of the same signals that common anti-inflammatory drugs target. Study sizes and doses are not on file, so this stays preliminary. Evidence grade C · Traditional tier T0 Colds, flu and other viral chest infections Early evidence — emerging human trials, including trials run during the COVID-19 pandemic. Emerging trials, including ones run during the COVID-19 pandemic, point to milder and shorter illness when it is started early. In lab studies it blocked how viruses enter cells and copy themselves. It also acted as a zinc carrier in lab work, helping zinc get inside cells. Evidence grade C · Traditional tier T0 Hay fever, sneezing and itchy eyes Not yet tested in people — lab work on mast cells only; no human allergy trial on file. In lab studies, it steadied mast cells. Those are the immune cells that set off allergy symptoms. No human hay fever trial is on file here, so we cannot say what it does for your nose or eyes. Evidence grade insufficient · Traditional tier T0 Blood sugar swings after meals Not yet tested in people — lab enzyme and cell studies only; no human trial on file. In lab work, it slowed some enzymes that break down carbs. It also helped sugar move into cells in lab studies. No human trial of blood sugar or insulin response is on file here. Evidence grade insufficient · Traditional tier T0 Heart health and blood flow Not yet tested in people — lab measures of LDL oxidation; no human outcome trial on file. In lab measures, it shielded LDL cholesterol from oxidizing. That step matters in how plaque builds up in arteries. No human trial of heart events or blood flow is on file here. Evidence grade insufficient · Traditional tier T0 Brain fog and memory loss with age Not yet tested in people — animal and lab studies; strong human data still emerging. In animal and lab work, it reached brain tissue. There it lowered markers of oxidative stress and inflammation. Solid human trial data is still emerging, so nothing here is settled. Evidence grade insufficient · Traditional tier T0 What Quercetin has not been shown to do It has not been shown to lower rates of heart attack or stroke; no human outcome trial is on file. It has not been shown to stop you from catching a virus; the trials looked at how bad and how long the illness was after early use. It has not been shown to treat diabetes or to replace blood sugar medicine. It has not been shown to prevent or slow dementia or age-related memory

Quercetin

Quercetin

Quick Facts

  • What it is: Quercetin is a plant pigment (flavonoid) found in many fruits, vegetables, and herbs — one of the most abundant antioxidants in the human diet.
  • Main uses: Most used for allergy relief, reducing inflammation, supporting heart health, and bolstering immune defense.
  • Best for: Seasonal allergies, Chronic inflammation, Heart health
  • Active ingredients: Quercetin (aglycone), Quercetin glycosides (e.g., isoquercetin, rutin), Quercetin phytosome (complexed with phosphatidylcholine for enhanced absorption)
  • Forms: Capsule, Tablet, Powder, Softgel (phytosome form), Liquid extract, Chewable
  • Time to effect: Allergy and inflammation relief: 1–4 weeks; antioxidant and cardiovascular benefits: 6–12 weeks of consistent use.
  • Side effects: Generally very well tolerated at standard doses; high doses may occasionally cause headache or tingling sensations.
  • Pregnancy & breastfeeding: Avoid in pregnancy and while breastfeeding.

Educational information, not medical advice — ask your doctor or midwife.

What is quercetin?

Quercetin is a flavonoid, a type of antioxidant commonly found in plants, fruits, and vegetables. It has gained attention for its potential health benefits, particularly in reducing inflammation and protecting against chronic diseases.

How does it work?

Quercetin has been shown to have various beneficial effects on human health, including its ability to reduce oxidative stress and inflammation, as well as its potential to prevent and treat certain chronic diseases. It is believed to work by inhibiting certain enzymes and pathways involved in inflammation and oxidative stress.

What are the active ingredients that are important for its medicinal properties?

Quercetin is the active ingredient responsible for its medicinal properties.

What forms does it come in?

Quercetin is available in supplement form, as well as in various foods such as onions, apples, berries, and tea.

When was it first used for medicinal purposes?

Quercetin has been used in traditional medicine for centuries, particularly in Asian cultures, to treat various ailments.

Who should avoid Quercetin?

  • Do not take quercetin with cyclosporine (a drug that stops organ rejection) unless your doctor approves it.
  • Do not take quercetin with warfarin (a blood thinner) unless your doctor is watching your clotting tests.
  • Avoid quercetin while you are on a quinolone antibiotic such as ciprofloxacin.
  • Do not start quercetin without asking your doctor if you take any daily prescription drug for your heart, blood or immune system.
  • Do not take more than 1000 mg a day on your own, since higher doses are not well studied.
  • Never take gram-size doses for many months in a row without a doctor checking in.
  • Do not take high doses if you have kidney disease or only one kidney.
  • Do not take high doses for months if you have a thyroid problem or take thyroid medicine.
  • Stop taking quercetin if your hands or feet start to tingle, and call your doctor.
  • Do not take quercetin powder on an empty stomach; always take it with food.
  • Avoid quercetin supplements if you are pregnant or breastfeeding, since safe use is not known.
  • Do not give quercetin supplements to a child unless a doctor tells you to.

When should you see a doctor?

Stop taking quercetin and call your doctor if your hands or feet tingle. Call also if you get a headache that will not go away. Changes in how much you pee need a same-day call.

Evidence grades and traditional-use labels are explained in our methodology. Nothing here is medical advice.

Remedies related to Quercetin

AstaxanthinBee PollenHistamine Support ComplexHyperbaric Oxygen TherapyLysineMethylsulfonylmethane (MSM)Neti Pot (Jala Neti)Nettle LeafQuercetin/Bromelain CombinationRosmarinic acidYerba SantaYu Zhu (Solomon's Seal TCM)

People take Quercetin when they say

Everyday descriptions of the problems this remedy is recommended for.

Conditions where Quercetin is recommended

Each grade below is for that condition specifically, not for Quercetin in general.

Natural options for Hay Fever (Allergic Rhinitis), ranked by evidence

The 5 options with the best evidence for Hay Fever (Allergic Rhinitis), each with its grade and who should avoid it. One email.

Occasional evidence updates after that — unsubscribe any time.