First I have to say that I have just began taking this product. I do take thyroid meds so I did have to make sure there’s is no interaction, I have not felt that there is any. I also looked up information first before me trying this product. It is safe and I just started taking it less than one week. I don’t feel any side effects and it is probably to soon to make an actual true or certain statement, because I have not taken them long enough. However, this seems to be an important and crucial supplement?a vitamin that I intend to continue to take in the future. I sometimes take a multi-vitamin however it does not contain Quercetin. Also I did not taste any after taste.