I just read a decent MedPage Today article by a researcher that states that it's more beneficial to regularly take vitamin D-even if the dosage is low. They only studied Vitamin D taken orally. In the comments people talked about their own results-including side effects from too much vitamin D. I think that Vitamin D has so much going for it, but that's been known since the 1930s and that's why the FDA has vitamin D in milk. I always buy milk with vitamin D.