I’ve been taking 5000 to 7000 IU of D3 for several months and was taking 3000 IU before that.
Before hip replacement surgery last June, my surgeon prescribed D3 for the month prior to surgery and the month after. The dose he gave was 5,000 IUs/day. I felt so good that I never stopped. I get D3 other ways, too, so about a total of 6500 IUs/day now. Knock wood, but I haven’t been sick, or even feeling a little punky. He also prescribed 1,000 of C, which I’ve continued as well.
D3 is fat soluble, so to make the most of it, have some fat@ the same time.
I take, and have been for years; 3-4000iu/day, at that level and higher, I would recomend taking K2, to put the extra calcium where it belongs.