Hay fever season is looming, and many allergy sufferers may be wishing they had a way to prevent the misery of sneezing and sniffling. One reader made a serendipitous discovery: quercetin taken for glaucoma calmed allergy symptoms quickly. What should you know about this supplement?

Quercetin for Glaucoma and Allergies:

Q. You’ve written about NasalCrom for allergies and I ordered it with high hopes. I also have glaucoma and wanted to get off Nasacort although it is working beautifully for my nose. I also take Xyzal or Zyrtec daily. Sad to say, despite using it two or three times a day for three months, NasalCrom did not seem to do anything for my allergies.

I did stumble across a supplement that seems to help–quercetin. It may reduce the risk of glaucoma, specifically benefiting retinal cells (Frontiers in Molecular Neuroscience, Sep. 7, 2017).

Oddly, I found that it helps with allergies too! I would be verging on breakthrough sneezing and found the symptoms settle down within 20 minutes of taking quercetin. You are supposed to take twice a day. Imagine my surprise when I checked the reviews and read that others also reported relief from allergy symptoms.

What Is Quercetin?

A. Thank you so much for alerting us to this approach to managing allergy symptoms. Quercetin is a flavonoid compound that is found in many different plants. Onions, kale and apples are particularly good sources of quercetin in the diet. Capers, berries, Brassica vegetables like broccoli or cabbage, grapes and tomatoes are other foods that contain quercetin (Nutrients, March 15, 2016).  Even tea has a small amount.

When we checked the medical literature, we were quite surprised to find research showing that quercetin is more effective than cromolyn (the active ingredient in NasalCrom) in blocking the inflammatory compounds released by mast cells (PLOS One, March 28, 2017). These studies were conducted in tissue cultures, and this compound might not be as effective when it is taken as a dietary supplement. However, research in rats suggests that it may ease allergic rhinitis, aka hay fever (European Archives of Oto-Rhino-Laryngology, Aug. 2017).

We’d love to see a clinical trial in humans, but they are expensive. Quercetin, as a natural compound, cannot be patented and therefore it is unlikely such a study will be conducted.

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  1. Cindy
    northern California

    One capsule a day of stinging nettle works great for me. It is inexpensive. I have recommended it to others. One friend has me order her some too because it has eliminated post nasal drip from allergies. It is good to know quercetin works too.

  2. Marla

    I’ve been giving quercitin to our dog for a couple of years to help with her allergies. Quercitin works best when combined with bromelain (an enzyme in pineapples) and papain (an enzyme in papaya).

  3. Margaret
    Buffalo, NY

    I was prescribed Quercitin for gerd symptoms. I was told that it is a powerful protector of the esophageal lining. Is this true?

  4. Jan

    I’ve been taking D-Hist for about 4 years, instead of other antihistamines like Claritin or Allegra. It contains quercetin, bromelain, stinging nettle, and N-Acetyl cystein. I take it once-twice a day during seasonal allergy season, and as needed other times of the year. I also react to scented laundry products and air fresheners, and this seems to calm my reaction within 20 minutes or so.

  5. O.G.
    South Carolina

    Isn’t it interesting how different things work (or don’t) for different people? I tried quercitin supplement for months once, to no effect. For me, Nasalcrom (and, if necessary, steaming my sinuses with sage and eucalyptus tossed into the water as it comes to a boil — hint: be careful of the hot steam!) was more effective. But I don’t use any conventional sinus medications, either. Perhaps that changes the equation.

  6. Isabel

    Could this be helpful for asthma sufferers?

  7. Ann

    Capsules work great for me but I take it at bedtime because it makes me drowsy. Natural Factors is my favorite brand for supps, and they make quercetin. Their products are made in Canada and they use mass spectrometry to check for contaminants. Can get it at Sprouts Market.

  8. Jane M.

    Hi! I have horrible allergies. I discovered Bromelain sinus ease that contains quercetin. I think the combo of quercetin and Bromelain works incredibly well for me. I take 3 pills per day with muscinex 400mg, and I’m cured.

  9. Pat B

    I don’t typically get seasonal allergies but long ago I read that quercetin can be helpful in easing symptoms. I have used it ever since to control the itchy eyes, runny nose, and sneezing for the occasional bout. It’s been very effective without any side effects. I gave some to a nephew who suffers from allergies regularly, and he also found it to be helpful. I take two 500 mg capsules when symptoms are annoying, 1000 mg of vitamin C, and 100 mg citrus bioflavonoids from citrus.

  10. MarieS

    I too tried NasalCrom without success. I am going to give quercetin a try!

  11. Dagny
    Philadelphia, PA

    I’ve found Quercetin to be helpful sometimes, but sometimes not. Because I’ve found NasalCrom to be helpful consistently, and because it doesn’t affect my entire body as a pill does, I stick with that although I wish there were local sources to buy it. I’ve only found two online retailers who sell it, and one of them seems to have trouble getting it from time to time.

    Another thing I’ve found VERY helpful is avoiding dairy products during allergy season, which for me stretches from spring (tree pollen), skips summer (grass pollen), and really rears up when the ragweed starts to bloom in the fall. It’s old fashioned medical wisdom that dairy products create mucous. Onions and garlic seem to be good for hay fever and just about any other sort of respiratory problem, so I have lots in my meals when I’m sure I’m not going out.

    I’ve tried Bromelain, a derivative of pineapple, and got diarrhea for my efforts. Canned pineapple in juice is probably just as good for the purpose with the same benefits and side effects, plus you can control the “dosage” better. Also beware of first generation antihistamines, the kind that make you sleepy. I not only had memory problems after taking Diphenylhydramine on a consistent basis, but it triggered headacheless migraines, something I experience only rarely when under a great deal of stress.

    Please keep in mind that I’m not a medical professional, just a self-educated health nut, and my advice is based on my own, possibly quirky experience.

  12. Elizabeth M.

    My husband has horrible allergies, and we discovered Quercetin and stinging nettles two years ago. They worked wonders for him! He takes them daily during allergy season, and we haven’t bought OTC allergy medicine since :)

  13. Lisa
    San Diego

    I take quercetin daily to help reduce my frequency of sinus headaches from my gardening and landscaping work and exposure to dust/pollen. It has helped me for years.

  14. Denise
    Sarasota, FL

    I had terrible allergy problems when I moved to a new area of the US. I started taking a generic of Claritin and found some relief, but it would wear off in the afternoon. Someone suggested Quercitin, so I tried it. I now take it every morning with my allergy pill. It boosts the effectiveness, and I no longer have symptoms at the end of the day.

  15. Migraine sufferer
    St. Louis

    What is the dosage for Quercetin?

  16. Linda
    cumming, ga

    How much quercetin do you take a day?

  17. Jennifer W.

    You didn’t address glaucoma being treated by Quercetin. I would like to hear your thoughts about that.

  18. paul
    Garland tx

    I think this is suspect. My wife, who is the most knowledgeable person I know about healthful eating, did not know of this substance. To be found in such a variety of sources it must be a moiety of a larger biomolecule we already know about. The science on it is simply too fresh. This sounds like the essence of a marketing scheme. I suggest you scrutinize your source. Might they be intimately associated with this compound and its financial future?

  19. Brent
    NW IL

    I’ve used this in combination with bromelain (pineapple enzyme) for years for my asthma and also use stinging nettles. Those work well. You could also try creating your own concoction with apple, onion and pineapple, as I’m sure that could even be more effective. Try mixing the first two with pineapple juice, and you should really get a healthy kick!

  20. AFB

    I’ve been using it for several years now. I take one in the morning and one in the evening. I’d say it’s eliminated 80% of my allergy symptoms (though I keep some of the sprays on hand for the rare occasions that things get out of control).

    At one point, I stopped taking Quercetin, just to make sure there wasn’t some other reason for my improvement. Within several days, my allergies started getting bad again. Since then, I’ve used it consistently and have recommended it to others. Normally, I’m skeptical of herbal supplements and the like, but this one works for me. And it doesn’t have any side effects that I’ve noticed.

  21. Kay
    Superior, WI

    I started both Nasalcrom and Quercetin again. When I took Quercetin before I took it once AM before breakfast and once PM with my Thyroid medicine. My thyroid test came back skewed, and my internist wanted to change my dose. I said “Let’s wait a while and see what happens.” The next thyroid test, full panel, came back all within range. What changed? I stopped taking the Quercetin with my thyroid medicine PM. Just thought that everyone needed to know that.

  22. Elle

    Quercetin was recommended to me for hay fever by my naturopath. I take a combo quercetin + ester C formula. I need to take two capsules twice a day but it works. My symptoms are greatly reduced.

  23. Carol
    North Carolina

    Just a note about quercetin: If taken for many years and at high dosages it may damage your kidneys. I discovered this after taking it for 20 years or so to treat the symptoms of interstitial cystitis. In the later years I doubled the dose. Over time it seemed to lose efficacy. I stopped using it several years ago, and my kidneys are now stable. (I now use Prelief for the IC).

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