The salvage pathway is used to produce NAD+ from nicotinamide molecules. Whether the source of the nicotinamide is vitamin B3 (as niacinamide), newer nicotinamides (e.g., nicotinamide riboside [NR], nicotinamide mononucleotide [NMN]), or molecules in food that get broken down during digestion into nicotinamide, the salvage pathway turns them into NAD+ in our tissues.