Quercetin Side Effects and Interactions 2021
Quercetin is an antioxidant that belongs to a class of water-soluble plant substances called flavonoids, which are present in certain fruits and vegetables. It can be found in high quantities in tomatoes, red wine, onions, green tea, apples, berries, and Gingko Biloba.
Quercetin Side EffectsWhen taken by mouth: Quercetin is POSSIBLY SAFE for most people when taken by mouth short-term. Quercetin has been safely used in amounts up to 500 mg twice daily for 12 weeks. It is not known if long-term use or higher doses are safe.
Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:
- Blurred vision
- dull ache or feeling of pressure or heaviness in legs
- fluid accumulation in the knee
- itching skin near damaged veins
- pounding in the ears
- red or scaling skin
- slow or fast heartbeat
- swollen feet and ankles
- tingling of the arms and legs
- stomach upset
Special Precautions & Warnings:
Kidney problems : Quercetin might make kidney problems worse. Don't use quercetin if you have kidney problems.
Quercetin Interactions - WebMD
Quercetin may interact with a number of medications:
- Antibiotics: May prevent the action of antibiotics
- Blood thinners: Could increase the effects of blood-thinning medication
- Chemotherapy: May interact with chemotherapeutic medication
- Corticosteroids: Could cause these medications to stay in your body for longer
- Cyclosporine: May interact with the absorption of this medicine
- Digoxin: Could increase the risk of side-effects associated with this chemical agent
- Fluoroquinolones: May decrease the effectiveness of these medicines
- Medications altered/activated by the liver: Quercetin may change how your body metabolizes medicine that is activated in the liver
Antibiotics (Quinolone antibiotics) interacts with QUERCETIN
Some of these antibiotics that might interact with quercetin include ciprofloxacin (Cipro), enoxacin (Penetrex), norfloxacin (Chibroxin, Noroxin), sparfloxacin (Zagam), trovafloxacin (Trovan), and grepafloxacin (Raxar).
Cyclosporin (Neoral, Sandimmune) interacts with QUERCETIN
Cyclosporin (Neoral, Sandimmune) is changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down cyclosporin (Neoral, Sandimmune). Taking quercetin might increase the effects and side effects of this medication. Before taking quercetin talk to your healthcare provider if you take cyclosporin (Neoral, Sandimmune).
Medications changed by the liver interacts with QUERCETIN
Some medications are changed and broken down by the liver. Quercetin might decrease how quickly the liver breaks down some medications. Taking quercetin along with these medications that are changed by the liver might increase the effects and side effects of your medication. Before taking quercetin talk to your healthcare provider if you take any medications that are changed by the liver.
Some medications that are changed by the liver include paclitaxel (Taxol), rosiglitazone (Avandia), amiodarone (Cordarone), docetaxel (Taxotere), repaglinide (Prandin), verapamil (Calan, Isoptin, Verelan), celecoxib (Celebrex), diclofenac (Voltaren), fluvastatin (Lescol), glipizide (Glucotrol), ibuprofen (Advil, Motrin), irbesartan (Avapro), losartan (Cozaar), phenytoin (Dilantin), piroxicam (Feldene), tamoxifen (Nolvadex), tolbutamide (Tolinase), torsemide (Demadex), warfarin (Coumadin), amitriptyline (Elavil), codeine, flecainide (Tambocor), haloperidol (Haldol), imipramine (Tofranil), metoprolol (Lopressor, Toprol XL), ondansetron (Zofran), paroxetine (Paxil), risperidone (Risperdal), tramadol (Ultram), venlafaxine (Effexor), lovastatin (Mevacor), clarithromycin (Biaxin), cyclosporine (Neoral, Sandimmune), diltiazem (Cardizem), estrogens, indinavir (Crixivan), triazolam (Halcion), verapamil (Calan, Isoptin, Verelan), alfentanil (Alfenta), fentanyl (Sublimaze), losartan (Cozaar), fluoxetine (Prozac), midazolam (Versed), omeprazole (Prilosec), lansoprazole (Prevacid), propranolol (Inderal), fexofenadine (Allegra), amitriptyline (Elavil), amiodarone (Cordarone), citalopram (Celexa), sertraline (Zoloft), ketoconazole (Nizoral), itraconazole (Sporanox) and others.
Medications moved by pumps in cells (P-glycoprotein Substrates) interacts with QUERCETIN
Some medications are moved by pumps in cells. Quercetin might make these pumps less active and increase how much of some medications get absorbed by the body. This might cause more side effects from some medications.
Some medications that are moved by these pumps include diltiazem (Cardizem), verapamil (Calan, Isoptin, Verelan), digoxin (Lanoxin) cyclosporine (Neoral, Sandimmune), saquinavir (Invirase), amprenavir (Agenerase), nelfinavir (Viracept), loperamide (Imodium), quinidine, paclitaxel (Taxol), vincristine, etoposide (VP16, VePesid), cimetidine (Tagamet), ranitidine (Zantac), fexofenadine (Allegra), ketoconazole (Nizoral), itraconazole (Sporanox), and others.
Quercetin DosageMost quercetin studies use a dosage of around 500 mg per day, although some studies use a dosage of 500mg taken twice per day.
Most supplements have a similar dosage, offering 500 mg to 1,200 mg of quercetin per serving.
In some studies, researchers have given participants up to 5,000mg of quercetin per day with no reported side effects.
Quercetin has poor bioavailability. You might take a 1,200mg quercetin supplement, but your body only absorbs a small percentage of it. That’s why many quercetin supplements contain vitamin C or bromelain, as some evidence suggests they boost absorption.
There’s also some evidence that quercetin has a synergistic effect when combined with other flavonoid supplements. That’s why some quercetin supplements contain resveratrol, catechins, genistein, and other flavonoids.
Conclusion: Side Effects of QuercetinIn summary, Quercetin is a great supplement for anybody looking to boost their health and well-being. It offers immune support and has powerful anti-inflammatory effects. Quercetin may also help to improve energy levels and to reduce stress. To check out the full list of benefits of quercetin with scientific references, visit proven benefits of quercetin.
Quercetin side effects are minimal and this plant-based dietary supplement is generally considered safe at the recommended dosages. High doses may cause headaches and an upset stomach.
There are some warnings about Quercetin side effects regarding interactions with various medications (listed above), and it should not be used by pregnant or breastfeeding women.
Medical Disclaimer: Not intended to treat, diagnose, or cure any disease or ailment. Please read and fully understand potential adverse effects before using this product. These statements have not been reviewed by the FDA. Please consult your doctor before using any supplements, especially if you have any medical conditions.
Related: Best Quercetin Supplement