I know my endo said it is important for building bone. I may be confused. Do you have osteo? I have osteo but have good d levels but my doc still has me taking calcium with vitamin d. I think I take 2 600calcium with 400of vitamin d. My mom has low d levels and is on prescription I think once a month or week not sure. Is your prescription?Hopefully Mrs D will come a long and give more answers and correct me if I am wrong.