Complete Omega-3.6.9-D provides the same balanced formula as Complete Omega-3.6.9, plus the added benefits of natural vitamin D3. This omega-rich blend supports cardiovascular health, brain function, positive mood, as well as healthy joints, hair, skin, and nails, while vitamin D3 promotes strong bones as well as healthy immune and neuromuscular function.* Vitamin D3 (or cholecalciferol) is the natural form of vitamin D produced by the body, and is better absorbed and utilized than other forms.