The version I purchased combines Quercetin with Zinc. I thought about taking it daily, but I have an underlying condition that might not mix well with it. I will mention it to my doctor, though, on my next visit.
The one I got was Quercetin plus nettles.
I have also been taking it daily. I figured it’s low risk with low (but possibly high) reward. For the most part it has mild anti-inflammatory properties but they were touting this since before covid that it showed help with lung inflammation, so I figured why not. I take one a day. The back-ups that I got in case I ever started showing symptoms were Brommalain, Tumeric and olive leaf extract.