42% of the adult United States population is deficient in Vitamin D and other regions of the world have severe Vitamin D deficiencies as well. Some of the symptoms of deficiency include: fatigue, muscle weakness, chronic pain, headaches, and depression. As you can see, these symptoms are very common and can be easily overlooked and dismissed by having other causes. Onjae offers up his experience with Vitamin D deficiency and how you can stay healthy by getting optimal absorption.