2000 IU is the tolerable upper intake level for
adults; supplementation over that may cause a risk for
toxicity (increased calcium, weak muscles, weak bones, excessive bleeding, severe headaches, and kidney stones). Vitamin D is available through our foods - Fortified milk, breakfast cereals, egg yolks, fatty fish, and fish oils. Sit at a window with the sun shining in for about 1/2 hour (few times a week) and that will help you get enough Vitamin D.