Vitamin D: How to Determine Your Optimal Dose
“Make sure you are getting the right test. You must test for 25(OH)D, not 1,25(OH)D. They look similar, but 1,25(OH)D is a measure of kidney function and is not the test you want for measuring vitamin D levels.
-Ideally, your blood level should be around 60-80 ng/ml, as this allows the body to have some vitamin D in reserve, and it duplicates the higher levels found in young, healthy individuals who spend a decent amount of time in a sun-rich environment.
-Begin taking vitamin D at least eight weeks prior to being tested. This will help you customize your dose once you receive your test results. To determine a basic, starting dose, it has been suggested, as per Dr. John Cannell of the Vitamin D Council (7), that you take 1,000 IU per 25 pounds of body weight. A person who weighs 150 pounds, for instance, would take 6,000 IU per day as a starting dose (150/25 = 6. 1,000 x 6 = 6,000). Do this for at least eight weeks, and then test. Perhaps this dose will put you in the ideal range, but there`s no guarantee since we are all so different, and have unique vitamin D receptor genotypes. The idea is to hopefully get somewhere in the ballpark with this method and then tweak your daily dose once the test results come back”