Adequate intake of vitamin D is imperative for skeletal and overall health. But what dosage does one take and how much is too much? The only way to ensure you are getting enough vitamin D is to ask your doctor to test. Your goal should be to maintain blood levels of 25-hydroxyvitamin D at 35 to 80 ng/ml.
In an examination of the literature, Dr. Michael Glade (2012) concluded “daily intakes of 600 to 800 IU of vitamin D are insufficient” and that “disease resistance requires daily vitamin D intakes of at least 1,500 IU.” As for safety, Dr. Glade concludes “long-term daily intakes of up to and including 10,000 IU of vitamin D maximize physiologic benefits and are safe.”
For my patients, I recommend a daily maintenance dose of 2,000 IU. If they are deficient, then I boost their daily intake to 5,000 IU for 2 months before retesting.
Glade, M.J. 2012. A 21st century evaluation of the safety of oral vitamin D. Nutrition 28(4):344-356.