stealth pathogens block up the "vitamin d" pathways in the body ( I don't like the term at all, but will use it be clear). Your doc will probably not put in the time to sort it all out as there are no quick and easy answers... A few years back I did all the homework to understand it. But to confirm, I had my chiro use muscle testing to check on key parts of the hypothesis, specific to my body... and it all checked out (much to my doctor's shock as he was recommending that I take vitamin D). I don't think that he will ever recommend that supp again. the problem is that the more you take, the more that the pathways get gummed up, and the pathogens get strong. sure you can feel better short term (as the immune system is slowly strangled), but that is no long term solution.