You may have heard the terms NMN and NR in relation to NAD+, but you might not know what they are specifically. NMN and NR are precursors to NAD+, meaning they become NAD+ through a series of chemical transformations. NMN has trouble entering our cells easily and one way for NMN to enter the cell is for it to chemically transform into another molecule beforehand. NMN sometimes becomes NR before entering the cell, where it chemically transforms back to NMN and then ultimately becomes NAD+. This obviously isn’t the most efficient way of creating NAD+ in the body. NR is a little more efficient than NMN because it can enter the cell as it is. It has its own pathway that allows it to skip certain steps that other NAD+ precursors, such as NMN, have to take. However, it’s not as efficient as simply supplementing with pure NAD+.