Want to know the differences and details of all of the NAD+ precursors? Trp (Tryptophan), NA (Nicotinic Acid), NAM (Nicotinamide), and NR (Nicotinamide Riboside)? They are surprisingly different:
Balancing NAD+ deficits with nicotinamide riboside: therapeutic possibilities and limitations 2022 link.springer.com/article/1...
Nicotinic Acid still looks like the best option to my High School educated brain.