I have been taking quercetin and zinc for a week, and I have some epigallocatechin-3-gallate. I wouldn't take either of those polyphenols without studying out retinotoxicity, ototoxicity, and hepatotoxicity data. Side effects can be dose dependent, but I have seen different datapoints, so don't just assume the first data you come across are correct. No one needs to turn yellow and die from ignorant attempts at DIY prophylaxis. My own doses may be too light to do any good, but I'm not looking to wreck my organs with higher doses.