If you�re one of the approximately 75% of Americans who are deficient in vitamin D, look no further. Doctor�s Best�Vitamin D3 is a �sunshine vitamin� needed to maintain strong bones and teeth and provide optimal immune function.* If you are not spending a lot of time in the sun or eating certain foods like fatty fish, fortified milk or eggs, you�re likely deficient in vitamin D. It�s totally normal�most people supplement to maintain adequate D3 levels�and it�s an easy fix with our array of vitamin D3 products.*