My vitamin D level was round 25 when I had it checked post Mirena just over two years ago. I took 2000 a day and got it up to 32. I went up to about 5000 a day and got my level up to 42. As I understand, 50 is optimum. My Dr sent me for a bone scan after my first test and I was very close to osteopenia in the femor neck...spelling ? It took an adjustment for me to go from 2000 to 5000, I can't imagine taking 100k without tapering on to it. I will also have to take it the rest of my life. My Dr says to go out in the sun for fifteen minutes a day, the dermatologist says not too. Who knows ?