1. NAD

Nicotinamide adenine dinucleotide is the molecule we’re actually after to get the benefits of NMN or NR. The problem is that it isn’t absorbed well by supplementation. 

2. NMN

Nicotinamide mononucleotide (NMN) is the step before NAD is made and it contains an extra phosphagen group over NR. That may be beneficial in terms of energy production, or it’s possible that it’s not more powerful than NR.

3. NR

Nicotinamide riboside is like NMN, but without the phosphagen group attached. It was theorized to be better absorbed than NMN, but more recent studies show that is most likely not the case and there may be slightly more benefits to NMN (endurance/cardiovascular). However, NR seems to perform just as well as NMN in most studies on anti-aging and at least for now supplementing with either in the 100-250mg range looks to be appropriate over the long-term.