Over the past 3 1/2 years I have slowly bougrht my level from 14 ng/ml ! to a recent (April '11) level of 63 ng/ml. It required a dose over the past year of .15,000 to 20,000 IU DAILY, as lower 5,000-10,000iu dosages failed to raise me above 44ng/ml . (I even found a bogus product through the Internet which allowed me to plummet from 44 in the spring of 2010 to 27 in the fall). I am curious as to whether this interval is due to my stature (6'5 and 275lbs) ? or simply a long standing deficiency ( I moved to northern Michigan in the early 80s and soon began experiencing complaints I now recognize as potentially related to a lack of Vit D )