Vitamin b complex contains: thiamine (vitamin B1), riboflavin (vitamin B2), niacin (vitamin B3), pantothenic acid (vitamin B5), pyridoxine (vitamin B6), biotin, folic acid and the cobalamins (vitamin B12). B vitamins are usually best taken together as a complex to increase their effectiveness. They play a vital role in cellular respiration and help to turn food into energy. This complex helps your body to properly digest proteins, carbohydrates and fats and convert them into energy. B vitamins play a vital role in maintaining a healthy digestive and nervous system, muscle function and heart health. It also aids the body's growth and immune functions. Quest's unique formula has added vitamin c to improve absorption and assimilation.