Riboflavin is a vitamin (B2) of the vitamin B complex; it is a precursor of flavin mononucleotide (FMN) and flavin adenine dinucleotide (FAD). Riboflavin is essential for the activities of various enzymes involved in the breakdown and utilization of carbohydrates, fats, and proteins, the production of energy in cells, the utilization of other B vitamins, and the production of hormones by the adrenal glands.


Rich sources of riboflavin are liver, milk, eggs, whole grains, brewer's yeast, and green vegetable.


Prolonged deficiency of riboflavin impairs growth and may cause chapped lips, soreness of the tongue, and corner of the mouth, and certain eye disorders, such as amblyopia (poor visual acuity) and photophobia (abnormal sensitivity to bright light).


People susceptible to deficiency include those taking phenothiazine antipsychotic drugs, tricyclic antidepressant drugs, or estrogen-containing oral contraceptives, those with malabsorption disorders, or those with severe alcohol dependence. Riboflavin deficiency may also occur as a result of serious illness, major surgery, or severe injury.