A blood test showed my vitamin D level is low. How do I know how much vitamin D to take?
As discussed in the Vitamin D Supplements Review, a good target range for blood levels of vitamin D is 25 to 35 ng/mL, as this coincides with maximum benefit. If you are below this range, there is a rule of thumb for dosage you can follow to get you to your target level -- be sure to take vitamin D with your biggest meal of the day, as you'll absorb more due to fats in your food. Of course, you can also increase levels by a certain amount of sun exposure and/or consuming foods containing vitamin D.