A new human clinical study by Nestlé found that supplementation with nicotinamide mononucleotide (NMN) and nicotinamide riboside (NR) increased circulating NAD+ levels in healthy adults, while also interacting with gut microbes to produce nicotinic acid and enhance other microbial activities. Nicotinamide, which was also tested in the study population, didn’t have the same effect.

NAD+ is a key co-enzyme that supports cellular energy production, DNA repair, and certain cellular functions. NAD+ levels naturally decline with age, and low NAD+ levels are associated with health conditions including cognitive decline, cardiovascular issues, muscle loss, and sleep disturbances.

The study findings, published in Nature Metabolism, indicate that NMN and NR could be beneficial in other areas beyond boosting NAD+ levels in the microbiome by promoting microbial growth and the production of beneficial metabolites.

In the study, 65 participants were administered either NR, NMN, or nicotinamide for 14 days. The former two supplements increased circulatory NAD+ concentrations in healthy adults and also interacted with the gut microbiota to produce nicotinic acid and enhance microbial metabolism.

“This is the first clinical study directly comparing different NAD+ precursors showing that NR and NMN supplementation can similarly increase NAD+ levels in healthy adults and may also support gut health,” said Eline van der Beek, PhD, professor at Utrecht University and head of the Nestlé Institute of Health Sciences. “These findings deepen our understanding of how NAD+ precursors can support healthy aging at the cellular level and pave the way for the development of innovative solutions to support healthy longevity.”