and the answer is that they don't work, and it goes back to what i was saying about pissing it out.
you might imagine that if you take a vitamin with 500% of your b1 in the morning then you're good for a week, right? a couple of days, anyways, surely?
but, no - what actually seems to happen (and, they've done studies, you can look this up) is that you get high on thiamin for a half hour, piss it out and crash. then, you're deficient for the next week.
we seem to have made a lot of bad assumptions about these sorts of things in the middle part of the last century. we assumed that you just absorb cholesterol in tact; in fact, you don't - it's regulated by your liver. and, we assumed that your body would find some way to manage a ton of vitamins if you administered it all at once; in fact, it can't - it gets overwhelmed and excretes the water soluble vitamins (and potentially even overdoses on fat soluble ones).
so, what multivitamins need to do is package smaller amounts and instruct people to take them 2-3x per day, instead of put together this overwhelming concoction and instruct customers to consume them daily or weekly.
so, i'm googling b5 and they all come in 50 mg, 500 mg or even 1000 mg dosages, and this is really just stupid. your body can't do anything with that except excrete it; it'll be pissed out in an hour.
if i could find a multi that has 5-10 mg of b5 in it (and reasonable amounts of other vitamins), i'd take it with each meal, as a fortification substitute.
but, i don't see the point in overwhelming myself with a chemical that my body is just going to go into overdrive to excrete. that's just likely to be harmful on my organs, in the long run.
i'd rather find a dietary source, it just doesn't seem feasible right now.