My dad(a nurse) recently tried to convince me that extra vitamin b12 or vitamins for that matter are excreted through the urine. So that this thing about building up your stores is false. please tell me what I can say to my dad to convince him that this is not true, cuz i believe it is not.

Oh yes, and recently I purchased lifefitness' rapid energy chewing gum, that contains vitamin b12, it doesn't go into specifics as to what vitamin b12 is in there, but I'm gonna guess it's cyancobalamin, cuz I mean they rarely ever use methyl. But whatever the case is, it's very convenient for energy on the go, and is better than caffeine for me.