I should add that to really know how much you should be taking, you should have your blood levels tested, as different people absorb it differently. Here's a po

I should add that to really know how much you should be taking, you should have your blood levels tested, as different people absorb it differently. Here's a post on William Davis' Heart Scan Blog (oriented toward heart health, which includes Vitamin D supplementation): http://heartscanblog.blogspot.com/2010/01/getting-vitamin-d-right.html http://heartscanblog.blogspot.com/2010/01/getting-vitamin-d-... He suggests about 6000 units/day as average.