Description: A B-complex vitamin is a mixture of the eight essential B-vitamins, including thiamin (B1), riboflavin (B2), niacin (B3), pyridoxine (B6), pantothenic Acid (B5), folic acid (B8), cyanocobalamin (B12) and biotin. Most of the B-vitamins play a critical role as cofactors in cellular energy metabolism. B-vitamins are important for hundreds of biochemical reactions in the body. B vitamin deficiency can lead to fatigue and lethargy, which is why B-complex supplements are excellent energy boosters and anti-stress formulas.