A Small Clinical Trial of NMN Fails to Produce Significant Results on Arterial Stiffness
Nicotinamide adenine dinucleotide (NAD) is involved in mitochondrial function, but levels decline with age for reasons that are not fully understood, alongside a loss of mitochondrial function. Thus there is some interest in delivering NAD precursor molecules, largely derived from vitamin B3, that can increase NAD levels. One might compare this trial of nicotinamide mononucleotide (NMN) with a similar trial of nicotinamide riboside (NR) a few years ago, which produced a better outcome, but still nothing to write home about. People who advocate for upregulation of NAD in mitochondria might say that the dosing is too low, but equally the long history of trying to increase NAD levels, accompanied by dozens of clinical trials, has little to show for it in terms of effect sizes that are any better than those produced by exercise. A good exercise program does still outperform NAD precursor supplementation, at least in clinical trial data.
Many animal studies have shown that oral administration of the nicotinamide adenine dinucleotide (NAD+) precursor nicotinamide mononucleotide (NMN) prevents the reduction of NAD+ levels in organs and tissues, helping alleviate aging-related diseases. However, there are very few clinical reports of NMN supplementation in humans. Thus, this study aimed to investigate the influence of a 12-week NMN oral supplementation on biochemical and metabolic health parameters.
A 12-week randomized, double-blind, placebo-controlled, parallel-group clinical trial was conducted. A total of 36 healthy middle-aged participants received one capsule of either 125 mg NMN or placebo twice a day. Among the NAD+ metabolites, the levels of nicotinamide in the serum were significantly higher in the NMN intake group than in the placebo group. Pulse wave velocity values indicating arterial stiffness tended to decrease in the NMN intake group. However, no significant difference was found between the two groups. Long-term NMN supplementation at 250 mg/day was well tolerated and did not cause adverse events. NMN safely and effectively elevated NAD+ metabolism in healthy middle-aged adults. Additionally, NMN supplementation showed potential in alleviating arterial stiffness.