Also in the US andI get the Jarrow Formulas brand Quercetin in 500mg capsules on Amazon. My doctor specifically recommended that brand so it’s the one I went with and it seems to be helping.

The cost has some variation throughout the month and occasional sales/specials to keep an eye out for. (Although I have not figured out the pattern) Sometimes the 100 count is cheaper than the 200 count or there will be a deal for buying two at once being cheaper than buying 1. Definitely play around with the options.

https://www.amazon.com/gp/aw/d/B0013OULOC?psc=1&ref=ppx_pop_mob_b_asin_title&th=1

A lot of the Querecetin that’s available has “Ester C” complex in it (must make it more able to be absorbed) and I wonder if the one that bothered you could have had some C in it, as that could absolutely cause a flare if so. The Jarrow brand is the only one I was able to find without it.

Jarrow Formulas Quercetin, for Cardiovascular Support, 500mg, 200 Capsules https://www.amazon.com/dp/B0013OULOC/ref=cm_sw_r_cp_api_glt_fabc_49SCAN130ZRZ81SHW0GF