Windmill Vitamin B-2 50 mg Tablets - 100 ea Dietary supplement. Essential for metabolism and energy production. No sugar, starch, yeast, wheat, milk, soy, artificial flavors or preservatives. Vitamin B2, commonly called riboflavin, is one of eight water-soluble B vitamins. Riboflavin aids in the metabolism of carbohydrates, proteins and fats to produce vital energy for the body. Riboflavin also helps support normal vision and skin health.