Most people who do not live near the Equator, even those living in sunny parts of the world, don't get enough Vitamin D conversion from the sun. Vitamin D is on the list of Anabolic Labs' 4 Essential Supplements to take (along with a Multivitamin/mineral, Magnesium, and Fish Oil). Vitamin D does allot more than help strengthen bones--it fights pain and inflammation, helps to regulate our immune system, making it strong but not over-active, and it helps with blood sugar regulation among many other things. It's not an expensive vitamin, either! Many people take Vitamin D year-round for optimal health.