|Safety of Quercetin|
At one time quercetin, like other flavonols, was considered as a possible carcinogen because it had demonstrated mutagenic effects on salmonella bacteria.3,15 Although some DNA damage has been noted in high-dosage quercetin lab studies (in vitro), these genotoxic effects were not observed when tested in vivo on rats and mice.16 In response to decades of numerous in vitro and in vivo studies, the International Agency for Research on Cancer concluded that quercetin is not carcinogenic to humans.12
Although considered safe, sometimes quercetin can cause headaches or an upset stomach, and there had been some reports of kidney damage at doses greater than 1-g/day.17 However, Memorial Sloan-Kettering Cancer Center notes that no adverse effects in humans have been reported taking doses as high as 4-g/day.18 Pregnant or nursing women should always consult with their healthcare provider prior to taking any supplement.
causing genetic damage.
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