The riboflavin coenzymes are Flavin Mono Nucleotide (Riboflavin-5-Phosphate) & Flavin Adenine Dinucleotide (FAD). Vitamin B2 occurs as flavoproteins in all cells of the body. In many of these flavoproteins, the flavin nucleotides are attached to an iron-sulfur complex (Fe S) metal ions such as zinc & molybdenum or to a heam. Contra-Indications If pregnant or breast feeding, consult your health care practitioner before using. For more information on this product contact your healthcare practitioner. This product should not be used as a substitute for a varied diet. Directions Recommended dose 1 drop per day in juice or water with a meal. Do not exceed this recommended dose unless prescribed by your practitioner.