Before you start popping Vitamin D tablets be sure to talk with your doctor. My doctor has me on 800 mg, which brought my blood level up to what it is supposed to be, my husband is on 4,000 for a month then dropping it down gradually after that. It was kind of a shock to find out you have to be outside without sunscreen in order to absorb the correct rays. In San Diego we have year round sunshine, so it was weird that we would have a Vitamin D deficiency, but we wear sunscreen religiously so it made sense that was why.