2. B Vitamins The B-complex vitamins, including B1 (thiamine), B2 (riboflavin), B3 (niacin), B5 (pantothenic acid), B6 (pyridoxine), B7 (biotin), B9 (folate), and B12 (cobalamin), play various roles in energy metabolism and are vital for the development of healthy tissues and organs. These vitamins also support the nervous system and overall cell function.