Ok, there's some slight inaccuracies in this thread:
a) when you stop taking vitamin A overdose the high level of vitamin A in your blood goes back to normal in under about a week, NOT months
b) however... the toxicity that you got from ODing on vitamin A can take several months to recover... you've literally been poisoning yourself; the good news is that it's rare that you will have any long term bad effects from it, but you wouldn't want to get toxicity because among other things it does BAD things to your liver (and your hair will fall out, and it doesn't *always* regrow, but nearly always does), but as I say, it will normally sort itself out in less than a year.
c) the toxicity is much the same as you get with accutane, but less safe (accutane is a version of vitamin A that has relatively low toxicity as these things go)
Somebody mentioned vitamin D. Basically forget about vitamin D. A toxic dose of vitamin D is about a whole bottle of pills per day everyday for three months. That's the acute toxicity.
For chronic dosing. the experiments there have been done say that if you're taking less than about 10,000-20,000 IU per day everyday for the rest of your life then you probably won't ever reach toxicity. FWIW a single pill is usually about 200 IU. So that's 50 pills everyday, and nobody is known to have died. The maximum *recommended* is calculated simply by dividing that (the highest known to be safe) by 10, 'just to be on the safe side'. And that's still a large dose.
Basically in terms of the ratio between what you normally take and what it takes to do you in, vitamin D is one of the safest chemicals there is. Oh yeah, and if you go out in the sun for about 15 minutes and sunbathe, that's about 10,000 IU, right there, made by your own skin.
Pretty much the only people that have ever died of vitamin D overdose were on special pills from their doctor that were 100x stronger; it's *incredibly* rare.
Actually, vitamin D *deficiency* is very common; like 20-30% of the population.
Yea, I stopped taking all of my supplements in late Novemeber of last year, but still am having slight symptoms of vitamin a toxicity....(been reducing month-to-month)
-slightly dry lips
-desquamation in parts of my face and upper neck
-sporadic, abnormal hair shedding
-intercranial pressure whenever i really exert myself in intense physical activity
and it can't be because of the weather cuz it's summer here with an average temperature each day from 60-85 degrees.
i read on this website (cant post link cuz mods will delete and/or ban me for a short-time) that it takes 200-300 days for the excess vitamin a to be used by my body.....
i figured the RDA for vitamin a for one year is around 1,000,000 iu's (365X3000)....
over the course of one year i consumed around 4,300,000 iu's (365X12000) in preformed vitamin a from supplements alone, not including all the other vitamin a i got from milk, ice-cream, cheese, and other animal origins....so i would say my body is good on vitamin a for a loooooong time. lol