Thanks Bass , @ 4 months ago I've done a test for Serum Vitamin D : 59 nmol/L ( 50 - 140 ) nmol/L , and after the result I have bought a bottle of 1000iu ,finish that ,after bought another one 5000iu , finish this one as well ,and the third one was 2000 iu .. I think it's time to stop now.. in...