Life Extension, Liquid Vitamin D3, 50 mcg (2000 IU), 1 OzProduct Description Liquid vitamin D3 is maintaining healthy levels of Vitamin D helps preserve youthful cognitive function and broad spectrum benefits for bone, immune system health and more. Here why you should be making sure you get enough of this essential vitamin. Vitamin D is important for maintaining cognitive health and function as you age. Healthy serum Vitamin D levels have been shown to correspond with better scores on cognitive health