Taking vitamin C for a cold
In 2007, researchers pooled the results of several previous studies and found that taking vitamin C won't make you feel better faster if you're already sick.
"After the cold is running its course, [vitamin C] doesn't have any effect," dietitian Andy Bellatti told us in July. "If you do have a cold, stay hydrated and get enough rest. Don't go to work and pound [vitamin C]."
[Photo via @aliceabdelaziz]