I have seen this before and even experienced it myself at 5000iu. The vit D causing these problems. It can last up to 2-3 weeks.. Dont know for sure this is the case, but maybe stay away from the vit D for a while and see if you benefit from it. I also thought it was strange since i took them for a very long time before i had the same problem. Maybe because the weather is improving and u get the vitamins trough the sun etc. u get an "overdose" which may cause the problem. I now take 5000iu once a week and thats fine for me.Originally Posted by austinite