>>9565098 (lb)
>As to studies that shows Quercetin's effectiveness against COVID-19
thanks anon!
Quercetin's effectiveness against COVID-19: "an Apple a day helps keep the doctor away"?
Apples and Onions contain some of the highest levels of quercetin.
While pure quercetin powder has poor water solubility and thus poor bio availability, natural foods rich on quercetin exhibit the best bioavailability (see paper attached).
excerpt:
Quercetin glycosides are mostly hydrolyzed and absorbed from the small or large intestines [6,8]. The physiological functions utilize the conjugated metabolites of quercetin in the plasma or other tissues, or the deconjugated aglycone in the specific tissues [8,16,17]. The intake of quercetin from dietary sources or supplements increases the plasma quercetin concentration [6]. Cao et al. reported that the mean intake over seven days of five flavonoids, including quercetin, was positively correlated to their corresponding plasma concentrations [18]. Ioku et al. showed that the quercetin glucoside content in onions did not decrease after frying or microwave heating [19]. Quercetin-4’-glucoside in onions was shown to transfer to the water during boiling without decomposition [19]. Thus, it is likely that the daily intake of food rich in quercetin increases the bioavailability of quercetin and contributes to the prevention of lifestyle-related diseases.