I started taking 10,000 IU a day for a month but was concerned about toxicity. I looked around for information about how much a person needs long term. No one could tell me, not even my doctor. He said it depended on how much I was in the sun.
I found a company named Permesys online and started reading about them. They use an algorithm that helps determine how much D you need based on many factors. It was totally free at the time. I took the test and called up their customer support and they set me on a 6 month plan. I get a differnet strength sent to me every month to keep my blood levels between 40-60 ng/mL. This product has the correct portion of calcium and magnesium too. I asked my doctor about it and he said it was fine. The product is called Sunshinebalance and 2 months into the vitamin D management program I feel great.
The reason no one tells you how much vitamin d you need is because it depends on so many factors. Go take the test and see.