Vitamin B1 has the molecular formula C12H17N4OS. It is a metabolic precursor of thiamine pyrophosphate, the form activated in the liver, which enables carbohydrates to be converted into energy and ensures proper functioning of the nervous and muscular systems. Synthesized by bacteria, plants and fungi, it is involved in energy metabolism, mood regulation, heart failure and muscle pain. Vitamin B2 is required for the synthesis of flavin adenine dinucleotide and flavin mononucleotide. It is most often isolated from milk as lactoflavin, from eggs as ovoflavin and from liver as hepatoflavin. It is effective against fatigue, supports the nervous system, helps maintain red blood cells and is involved in iron metabolism. It is also involved in keratin synthesis.