The SECOND you feel one coming on, it's ALL about zinc. Take zinc AND vitamin C with every meal.
I don't know why people assume this. It's long been proven that Vitamin C does absolutely nothing when it comes to reducing your chances of getting a cold or reducing it's time frame.
Zinc has been inconclusive at best with most studies showing no difference between zinc and a placebo. The ones that do show benefits have been so minimal that the side affects of zinc outweigh the benefits.
Take both if you think they work, but bottom line is that if you get a cold it's just going to have to run it's course.
I work in Finance so obviously I am an expert on such matters.