If you have some handy and can start using it when you first start getting that scratchy feeling, they work great. If you start getting sick at work and have to wait until you get home to get started, it doesn’t seem to do much good.
This has been studied before, in fact I believe that they found that the zinc stops viral binding to mucosal cells decreasing the spread and severity of infection.
Yeah, this was a study of studies and apparently done for the mixed results of past studies.