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

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).