The main side effects of quercetin

Quercetin is a flavonoid with antioxidant properties. There are many natural sources of this compound, including fruits such as apples and grapes, certain types of nuts, green tea, etc. In addition, the health benefits of red wine have been linked to its presence of this antioxidant. Flavonoids such as quercetin are often considered beneficial to health, and such supplements are often recommended to promote overall health. Flavonoids are water-soluble, so it is also easier to excrete the excess when consumed in excess. In addition to these positive effects, some serious side effects have been reported associated with excessive intake of quercetin.

Nutritional supplements containing quercetin are often used to treat allergies, diabetes, eye diseases caused by cataracts or retinal problems, and atherosclerosis, and are even recommended as anti-aging treatments. The amount of quercetin contained in different supplements varies, but 500-1500 mg per day is generally considered to be the most beneficial for health. However, some health experts believe that this dose is obviously too high, which can easily cause adverse reactions in some people. They believe that getting quercetin from a normal diet is a healthier way to go than supplements.

Quercetin Sophora Japonica Extract manufacturer, supplier & exporter- Shaanxi Porvoo
Quercetin Sophora Japonica Extract from Shaanxi Porvoo

What are the main side effects of quercetin?

The side effects of quercetin usually occur shortly after large dose intake, especially acid reflux is the most common one. Taking quercetin with or immediately after a meal can be effective in avoiding these minor side effects. Other negative effects that quercetin can cause include increased inflammation in the body. Although antioxidants have the ability to counteract inflammation in the body, large doses can easily cause the opposite effect and induce inflammation. Joint pain and stiffness are common manifestations of this side effect.

Other possible side effects include abnormal changes in hormone levels in the body. For example, estrogen, an estrogenic hormone, is particularly susceptible to high levels of quercetin. A study found that premenopausal women who took supplements containing quercetin had significantly higher blood estrogen levels than women who took supplements without quercetin. High estrogen levels are known to be potentially associated with a high risk of cancer of the female reproductive system and breast cancer.

Some researchers also believe that the side effects of quercetin may also include a high risk of causing specific cancers. Although normal doses of quercetin can help protect against some types of cancer, excessive intake can also have negative effects. This is because high concentrations of quercetin tend to cause DNA damage.

Because of the potential for genetic damage caused by quercetin, many health professionals recommend that pregnant women avoid consuming these supplements to avoid fetal genetic mutations.


The information contained in this article is only for information sharing, not as health or medical suggestions. You should not use it as a substitute for your own independent judgment and should always consult a physician or other qualified health provider for any questions you may have about your health status or health goals.

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