Question: Will zinc help prevent or shorten the length of a cold?
Answer: The studies of zinc have been mixed. So, there are a number of studies that have been done looking at the effect of zinc, primarily on the severity of illness and duration of illness. Those studies have been split really between studies that show fairly dramatic effects, and then an equal number of studies at least that show very little or no effect. So, I think it's a little hard to know exactly what the final answer is on zinc right now, although, in my opinion, I suspect that it doesn't have a whole lot of impact on common cold illness.