The same can be said for nicotinamide mononucleotide, a molecule called NMN for short. NMN is a precursor to NAD+, or nicotinamide adenine dinucleotide, meaning it becomes NAD+ through a series of chemical transformations. NAD+ is a critical found in every cell of your body, but levels of NAD+ naturally fall with age, making it — and NMN, as a result — crucial.
However, NMN is like a large bed that movers are trying to get through a door: It doesn’t enter the cell easily. One way for NMN to enter the cell is for it to chemically transform into another molecule (called nicotinamide riboside, or NR) before it can enter the cell. NR has
earned a name for itself as a highly efficient precursor to NAD+ and can enter the cell as is. NMN, meanwhile, sometimes becomes NR before entering the cell, where it chemically transforms back to NMN and then ultimately becomes NAD+.