There are a few differences between Nicotinamide Mononucleotide vs Nicotinamide Riboside. Nicotinamide Mononucleotide is not considered a form of vitamin B3 while Nicotinamide Riboside has shown to be a proven form of vitamin B3. In terms of structure, Nicotinamide Mononucleotide molecules are larger and weigh more than Nicotinamide riboside molecules. Nicotinamide Mononucleotide has shown positive effects on NAD+ levels in animal models and is currently being tested in humans.