so if I do take a supplement, I look for a large manufacturer with a good reputation, seek highly pure molecules (more than 98 percent is a good guide), and look for “GMP” on the label, which means the product was made under “good manufacturing practices.” Nicotinamide riboside, or NR, is converted to NMN, so some people take NR instead of NMN because it is cheaper. Cheaper still are niacin and nicotinamide, but they don’t seem to raise NAD levels as NMN and NR do.
