Comment by joveian

Here is a case study and discussion from a parathyroid surgeon:

https://www.devaboone.com/post/vitamin-d-part-2-shannon-s-st...

"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.

Unfortunately, none of those patients were warned about the potential for Vitamin D to cause high calcium. They all believed that they were taking a supplement to improve health and that there was very little risk. Supplements don’t require prescriptions, and most do not have the warning labels that accompany medications. For Vitamin D, a steroid hormone, that may need to change."