This is from memory, I don't have my sources right now, but most of what I've read is that the body can deal very well with too much Vitamin D. What it doesn't do well is a deficiency.
A few of my pharmacist friends told me about how some people are being prescribed doses of 50,000 UI, and I've read somewhere that below 14,000 UI a day over extended periods, no toxicity was found. So I kind of doubt that 2,000 UI is an upper bound, unless you have a very specific condition. Just spending a day on the beach probably gives you a MUCH higher dose than this.
But as I said, this is from memory. Take this with a grain of salt and do your own research. Personally, I'll keep taking my 4,000 UI/day, something that I've been doing for about 4-5 years (and while this is anecdotal, I've seen improvements in seasonal mood changes and the number of times I'm sick per year).
The 50,000 IU dose is a single dose, not a daily dose to be taken over some period of time. The half-life of vitamin D in the body is a few months, so a large single dose is effective for some time.
I'm not sure if I wrote it like that because I used to writing the acronym for "user interface" or because in French, my native language, they write it as "UI" (unités internationales). But thanks for the correction.
A few of my pharmacist friends told me about how some people are being prescribed doses of 50,000 UI, and I've read somewhere that below 14,000 UI a day over extended periods, no toxicity was found. So I kind of doubt that 2,000 UI is an upper bound, unless you have a very specific condition. Just spending a day on the beach probably gives you a MUCH higher dose than this.
But as I said, this is from memory. Take this with a grain of salt and do your own research. Personally, I'll keep taking my 4,000 UI/day, something that I've been doing for about 4-5 years (and while this is anecdotal, I've seen improvements in seasonal mood changes and the number of times I'm sick per year).