Nicotinamide mononucleotide (NMN) is a nucleotide that is the precursor to NAD+. It has been shown to reduce tumour heterogeneity and extend the lifespan of mice. The effects of NA and NAM supplementation on skin tumor incidence have also been reported.
NMN is highly stable and can be absorbed easily through the intestines. In addition, NMN is converted to NAD+ by enzymes called NMNATs. NMN is highly available in the body and can be found in vegetables, fruits, and meats.
However, the pharmacokinetics of NMN and NR are not fully understood. Further studies are required to understand how the two compounds interact with the body. Exploration of NMN and NR pharmacokinetics could contribute to determining the best concentration for various applications.
Studies on rats show that NAM can be directly absorbed by the intestine. Therefore, a diet rich in NAM may be useful in the treatment of pellagra.
Despite these advantages, NMN is not considered the ideal precursor for NAD+ supplementation. Compared to NR, NMN has more pharmacological properties. For instance, it can enter cells through equilibrative nucleoside transporters. A study on mice showed that the NMN supplementation reduced the growth of liver progenitor cells involved in tumour heterogeneity.
Both NMN and NR have a relatively short half-life. High doses of NMN or NR might require a minimum of three hours to be absorbed. Nevertheless, oral administration of NMN is generally tolerable.
Unlike NMN, NR does not undergo oxidative phosphorylation. This allows it to better take advantage of the salvage pathway.