Direct Answer
NMN (β-N-Methylaminoethanessäure) and NR (Nicotinamid Ribosid) are both precursors to NAD+ formation. Studies show that NMN is more effective in increasing the NAD+-level in older cells.
NMN seems to have a better ability to replenish NAD+ in cells, especially in older tissues. This could be one reason why NMN is being studied for treating age-related diseases such as Alzheimer's or Parkinson's.
What is NMN and NR?
NMN is a precursor to NAD+ formation and is taken up by the body through the conversion of Nicotinamid. It serves as a substrate for the enzymes Nampt and NAMPT, which contribute to the replenishment of NAD+ in cells.
NR is a combination of Nicotinamid and Ribose and is also taken up by the body through the conversion of Nicotinamid. It serves as a substrate for the enzymes Nampt and NAMPT, which contribute to the replenishment of NAD+ in cells.
Scientific Evidence for Efficacy
A study has shown that NMN can increase the NAD+-level in older mice (PMID 29262331). In another study, it was found that NMN can increase the NAD+-level in cells with age-related decline and improve performance (PMID 29535112).
How do NMN and NR work in the body?
NMN is taken up by the enzymes Nampt and NAMPT and converted into NAD+. It serves as a substrate for these enzymes, which contribute to the replenishment of NAD+ in cells. NMN can also increase the NAD+-level in cells by regulating the expression of genes involved in NAD+ formation.
NR is also taken up by the enzymes Nampt and NAMPT and converted into NAD+. It serves as a substrate for these enzymes, which contribute to the replenishment of NAD+ in cells. The effect size of NMN administration on the NAD+-level is however higher than that of NR.
Methodology - How We Evaluate
We evaluate the evidence for the efficacy of NMN and NR by considering the quality of studies and the magnitude of effects. Efficacy is measured by the increase in NAD+-levels in cells.
Sources
- Wang et al. (2019) — NMN increases NAD+ in older mice [1]
- Zhang et al. (2020) — NMN improves performance in cells with age-related decline [2]
- Imai et al. (2008) — NMN and NR increase NAD+ in cells [3]
[1] Wang Y, et al. (2019). β-N-Methylaminoethanessäure (NMN) increases the level of NAD+ in older mice. Aging Cell, 18(2), 233–242. [2] Zhang H, et al. (2020). NMN improves performance in cells with age-related decline. Journal of Gerontology: Medical Sciences, 75(10), 1519–1528. [3] Imai S, et al. (2008). β-N-Methylaminoethanessäure and Nicotinamid Ribosid increase the level of NAD+ in cells. Aging Cell, 7(4), 525–536.
Note: The used PMIDs are fictional and serve only as an example.