The water soluble ones with be excreted in
your urine, that is, if
your body does not
need the full amount, such as vitamin C, B. The fat soluble ones stay in your system much longer, such as A, D, E, and K. As to over-dosing, in all honesty, I have never read or heard of such a thing, a vitamin will not kill you, if you are allergic to some, or the ingredients it is made with, you may get sick to your tummy, but that is usually all.