Riboflavin-5 phosphate, also known as flavin mononucleotide (FMN), is a molecule that the body naturally produces from riboflavin (vitamin B2). Most riboflavin in the body is found in the form of riboflavin-5 phosphate. Riboflavin, along with most of the other B vitamins, is responsible for converting ingested carbohydrates to usable energy (glucose) and breaking down fats and proteins.
Riboflavin is also specifically responsible for proper skin development, as well as the maintenance of healthy digestive tract lining, blood cells, and other bodily systems. In the United States, foodstuff manufacturers are required by law to fortify the refined flour used in their products with riboflavin, thiamin (B1), niacin (B3), and folic acid (B9). Accordingly, riboflavin can be ingested from virtually any foods made with enriched flour, as well as various meats, milk, eggs, nuts, and green vegetables.
Though true riboflavin deficiency is rare and tends to manifest itself plainly, people use a riboflavin or riboflavin-5 phosphate supplement for acne, muscle cramps, athletic performance, carpal tunnel syndrome, eye conditions, headaches, immune support, alcoholism, liver disease, blood disorders, and Alzheimer’s disease.
Scientific trials have yet to be conducted on most of these uses, and while some studies indicate that taking a riboflavin supplement may reduce the frequency of migraine headaches and prevent the development of cataracts, the results have not been conclusive and ought to be considered preliminary. Riboflavin supplements should not to be taken to justify delaying a medical consultation, and not all information encountered on the Internet or other media about the efficacy of riboflavin should be treated as absolute truth.