While quercetin is generally pretty safe it does have some possible side effects. In this article, I’ll discuss both the known and possible quercetin side-effects.
If you research quercetin side-effects, you’ll soon find that no clear toxicity exists. So taking large amounts won’t immediately have any obvious ill effects. However, there is some theoretical and anecdotal evidence that consuming large amounts of quercetin regularly — especially with other antioxidants (especially Vitamin C) — can potentially manifest some problems in some people despite the many quercetin benefits.
As is the case with many antioxidants — especially bioflavonoids such as quercetin — taking too many antioxidants at once can result in a pro-oxidant effect. What this means is that the inflammation-reducing effects of supplements such as vitamin C and quercetin can actually instead cause inflammation if you take them both in very high doses.
Anecdotal evidence suggests that this manifests itself most commonly in joint discomfort after prolonged usage of quercetin.
People with sensitive stomachs may also experience heartburn or acid reflux if larger doses are consumed on an empty stomach. However, this side-effect can often be avoided by simply taking the quercetin in the middle of a meal instead of on an empty stomach. Some common sense in respect to the quercetin dosage you choose can go a long way to curbing negative quercetin side effects.
Again, it is important to understand that Vitamin C and quercetin can work great together if taken in reasonable doses. With supplements such as quercetin health can and will improve in specific areas if leveraging the supplement properly.
Taking A Quercetin Supplement
So how much Quercetin should you take to stay safe?
A regular quercetin dose is usually between 200 and 500 mg. A strong dose sometimes suggested is 800 mg. Most supplement manufacturers recommend taking it regularly through the day, so these doses are usually given three times a day.
There are very few situations where you would benefit from more than 2400 mg a day, so I suggest keeping that as the upper limit. I also suggest beginning with smaller doses to see how your body reacts to it. Please don’t rush in trying to help yourself faster by taking larger doses.
You should also consider drug interactions when using quercetin. As a baseline avoid taking quercetin with any medication that indicates you shouldn’t consume the following foods while using it: onions, apples, apple juice, grapefruit juice, orange juice, pomegranate juice; white, green & black teas.
These foods naturally contain higher concentrations of quercetin, so if a medication conflicts with them, you should also stay clear of a quercetin supplement while taking your medication.
In addition, the following medications are known to either be suppressed or exaggerated if taken in conjunction with quercetin: Cyclosporine, Estradiol, Felodipine
The interactions aren’t severe, so don’t panic if you’ve combined them already, but I would suggest immediately stopping your quercetin dosage and discuss all of your supplements with your doctor as soon as possible.
Some evidence also suggests quercetin may inhibit fluoroquinolones, a family of broad spectrum antibiotics. But to make it difficult, some evidence also suggests it may enhance these antibiotics. I suggest playing it safe and avoiding the interaction unless your medical professional states otherwise.
As always, of course, you should consult your doctor when making any of these decisions and considering quercetin effects on your overall medical regiment.
In general, be careful to keep your doses low and reasonable. Plant flavonoids may be more potent than many assumed just a few years ago, and there isn’t enough evidence to know for certain how that potency manifests itself.
Unless you know that quercetin has had a strong, positive effect on your health, I don’t suggest raising your total daily dosage above 1500 mg (that’s 3 separate doses of 500 mg… do not try taking 1500 mg at once), especially if you’re taking other bioflavanoids with your supplement regiment. I also suggest enhancing your supplementation with quercetin bromelain. Bromelain is a protease enzyme which helps your system digest and absorb quercetin.
I hope this helps you feel more confident and knowledgeable when considering possible quercetin side-effects and thank you for visiting.