I checked with a biologist I know who's been on top of this kind of thing. There have been other doctors recommending zinc and/or this combo too. Also, you can just start taking zinc supplements if you have them, as so many people are zinc deficient. It's not going to hurt you.

Studies are inconclusive. For a long time we thought that zinc lozenges shortened the duration of sore throats and colds, then a study came out recently that said there wasn't a significant difference. I don't know about you, but for me even half a day less of having a sore throat is significant -- so I'm going to keep using zinc lozenges if I start getting an itchy throat. Plus that was just one study.