Flavin Adenine Dinucleotide (FAD) is an essential coenzyme that takes part in many biochemical reactions in living organisms. It is commonly associated with oxidation-reduction reactions and energy metabolism. Some synonyms for FAD include flavoproteins, redox-active flavins, flavin coenzymes, and riboflavin-5′-phosphate. In addition to its role in energy production, FAD is also necessary for the functioning of certain enzymes and vital biological processes such as DNA repair. FAD is found in various foods such as meat, yeast, eggs, and milk. A deficiency in FAD can lead to many health disorders like headache, fatigue, and muscle impairment.