listened to Dr Z when he first came out with this protocol, found it at amazon in a single capsule, zinc-quercitin-C-d3, (i think the mfg is Spartis or something like that...not advertising, just sharing info)...anyhow, i've been taking it twice daily as the dose on bottle states, and haven't had anything viral in years...occasionally take ivermectin as preventative because i am around many dogs...odd that we worm all of our animals, but not ourselves...