*Of course, there is a selection bias in who comes to me. There are people out there doing just fine on 5000 units of Vitamin D daily. I only see the ones who develop high calcium levels. But I see enough of them to know that this is not an exceptionally rare occurrence. I have been to lectures in which physicians have claimed that Vitamin D toxicity almost never occurs. In my experience, this is false. I have seen many cases of Vitamin D toxicity in people who were taking the recommended dose from an over-the-counter bottle.*
I am also doing 4000IU in the half-autumn/winter/half-spring time and none during summer and doing blood work to test the levels and I am keeping it in 40ng/ml and from the article:
*...her blood Vitamin D level had risen to 79 ng/ml. This level is within what many labs call the normal range, between 30 and 100 ng/ml, but levels above 70 are almost always a result of high dose supplementation, and I have seen toxicity with levels between 70 and 100 ng/ml. (A better “normal range” based on what I have seen would probably be between 30 and 60.) Vitamin D builds up over time, so the longer someone is on a high dose, the more likely she is to develop toxicity.*
Lady in the article was taking 5000IU daily for 5 years.