Premium Quality 100 mg Riboflavin Coenzyme Precursor Certified Potency Dietary Supplement Health through the power of nature—that's what it means to Trust the Leaf. Vitamin B2 (riboflavin) is a precursor to coenzymes involved in the growth and repair of skin and tissues lining the gastrointestinal tract, as well as the synthesis of amino acids. B2 is necessary for the formation of pigments essential to vision. Our Vitamin B2 is carefully tested and produced to certified quality standards.