Getting too much vitamin D is associated with negative effects. With continued use of enormous doses of vitamin D, toxic effects can occur, which has been reported with the use of a protein supplement containing vitamin D.  My suggestion is to try to get 30-60 minutes of sun a day and if you live in the northern states and/or get little to no sunshine due to work etc during the day, do take a vitamin D supplement but be careful of  the amount.  I recommend no more than 5,000 IUs daily.