Source Naturals Inosine offers the fundamental nucleoside (building blocks of RNA and DNA) to support many functions in the human body. Inosine is a precursor to the energy molecule adenosine, which has made it a popular choice for athletes and those with high energy requirements. Inosine also provides support for neurological health. Contains no yeast, wheat, gluten, dairy, soy, egg, salt, sugar, starch, preservatives, or artificial color, flavor or fragrance.