B vitamins are a group of nutrients that are essential to numerous processes in the body. The list consists of thiamine (B1), riboflavin (B2), niacin (B3), pantothenic acid (B5), pyridoxine (B6), biotin (B7), folate (B9), and cobalamin (B12). Most of us know about them, as they are an essential part of every multivitamin supplement. As a group they are involved primarily in the chemical reactions of energy metabolism, as well as synthesis of a variety of compounds necessary to life. In an attempt to understand these vitamins as a system, let’s examine them as a group, looking for commonalities of function, and common symptoms of deficiency. Individual aspects can be explored if necessary.