Sure, you take a daily multivitamin—but do you have a solid grasp of what’s actually in it? There are a whole lot of letters on that label…

Don’t worry, you’re not alone if you don’t know the difference between vitamin A and vitamin K. After all, there are 13 vitamins in total, and each has a unique, health-benefiting function. We’ve got the CliffsNotes so you always know what nutrients you’re taking.