The vitamin B-complex is important for energy production, immune health and nervous system function. B vitamins play a vital role in cellular respiration and helping turn food into energy. Solgar Megasorb B-complex is formulated for optimal absorption and utilisation. Vitamin B-complex refers to all of the known essential water-soluble vitamins except for vitamin C. These include 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.