I just read an interesting fact while taking a quiz on vitamins and minerals which was presented on WebMD. Too much Vitamin D can cause weakness, irregular heart rate, and confusion. I have been taking 5,000 iu per day for 2 years as my neurologist directed me to do. I also have been experiencing all three of the above symptoms frequently. Is there a correlation? I do not know, but I do know that I am going to skip the vitamin D for a week and see if these symptoms ease off at all. Sometimes I really wonder about attempts to overcorrect our illness. The latest push seems to be massive doses of biotin which can only be purchased at compounding pharmacies and which also is not covered by insurance. Any thoughts on these issues? I appreciate your input. Thank you.