Quercetin is a flavonoid found in a variety of different plants and is claimed to provide several health benefits. Although it can be obtained through eating certain fruits and vegetables, it is also available in
dietary supplements.
Quercetin appears to have numerous different actions that could contribute to its medicinal activity. It seems to work as an antioxidant and may also have anti-inflammatory effects. It might inhibit the growth and division of certain cells, including cancer cells, and may have anti-estrogen effects (which could possibly contribute to some effect on hormone-related cancers, such as
breast cancer). For
allergies, it might work by inhibiting the release of histamine.
These are just a few ways that researchers have suggested that the substance may work for a variety of conditions. At this time, it is not fully known how the different activities of quercetin may work together (or even if the flavonoid really works for most uses).
Although research in laboratory animals or cells shows promise, there is not much evidence in humans to suggest that this flavonoid really works for most uses
(see
Does Quercetin Work? for more information).
As with most
dietary supplements, there is no well-established standard dosage for this substance, although general guidelines may be obtained from practical experience with the supplement.
Side Effects of Quercetin
Even though it is a "natural" product, quercetin can cause side effects. Some of the reported side effects include:
(Click Quercetin Side Effects to learn more, including potentially serious side effects that you should report immediately to your healthcare provider.)
For many adults, short-term use seems to be fairly safe when used in moderation. Some people may be more likely to experience problems due to quercetin. Therefore, you should talk with your healthcare provider prior to taking it medicinally if you have:
- Kidney disease, such as kidney failure (renal failure)
- Any chronic or severe medical condition
- Any allergies, including allergies to foods, dyes, or preservatives.
Also, let your healthcare provider know if you are:
Make sure to tell your healthcare provider about all other medicines you are taking, including prescription and non-prescription medicines, vitamins, and herbal supplements.
(Click Is Quercetin Safe? for more information, including any available warnings and precautions.)
What If I Take an Overdose?
It is not clear exactly what to expect from an overdose with this supplement. If you think you or someone else may have taken too much quercetin, it is important to seek immediate medical attention.
Storage Methods for Quercetin
Refer to the label of your individual product for information on how to best store quercetin. Keep all medications and supplements out of the reach of children.
