WebMD
https://www.webmd.com/vitamins/ai/ingredientmono-294/quercetin
Quercetin has antioxidant and anti-inflammatory effects that might help reduce swelling, kill cancer cells, control blood sugar, and help prevent heart disease.
Quercetin is most commonly used for conditions of the heart and blood vessels and to prevent cancer. It is also used for arthritis, bladder infections, and diabetes, but there is no strong scientific evidence to support most of these uses. There is also no good evidence to support using quercetin for COVID-19.
Does quercetin protect against COVID-19?
https://www.pharmaca.com/projectwellness/whats-the-relationship-between-quercetin-covid-19/
There is not enough evidence to show that quercetin can prevent or treat COVID-19. However, recent studies have shown that it may prevent COVID-19 from replicating within the body, helping to fight infection and lessen symptoms.
Hydroxychloroquine and Quercetin are Cousins - Health and Wellness in Life and Business
https://www.youtube.com/watch?v=hFm-vN5hNrk
