I took the 50,000 units pill once a week for 8 weeks and loved it. You can back and read all my posts, but I haven't felt as good since I got off the vitamins D prescription. I take 2000 units a day now off and on. I feel better the days I take it. We are so low on vitamin D because of Mirena, that we NEED an extra D supplement and because we are so low, I think it would take a lot to make us sick.