I take 4,000-6,000 UI of Vitamin D3 daily in gelcap/softgel format (Vit D is fat soluble, the dry tablets aren't absorbed nearly as well, which has been confirmed by blood tests).<p>It costs almost nothing. A bottle of 360 softgels each containing 2,000 UI costs about $25 (Carlson Laboratories brand).<p>Just make sure you also take enough vitamin A.