Nicotinamide adenine dinucleotide metabolism and arterial stiffness after long-term nicotinamide mononucleotide supplementation: a randomized, double-blind, placebo-controlled trial

Katayoshi T, Uehata S, Nakashima N, Nakajo T, Kitajima N, Kageyama M · Scientific Reports

Null on the vascular endpoint. Brachial-ankle pulse wave velocity fell by 25.1 ± 14.5 cm/s in the NMN group but the between-group difference was not significant (p=0.097). Serum nicotinamide rose against placebo (p=0.037 by analysis of covariance), while serum NAD+ and NMN were detectable but below the limit of quantification in both groups, so neither could be compared. Post-hoc subgroups with above-average BMI or blood glucose did show a significant fall in pulse wave velocity against placebo; the above-average blood pressure subgroups did not. Well tolerated.

Population

Healthy middle-aged adults

Intervention

NMN 125 mg twice daily (250 mg/day) for 12 weeks

Comparator

Placebo

Limitations

Seventeen to eighteen per arm — underpowered for a vascular endpoint. Serum nicotinamide differed between the arms at baseline (p=0.001), and it is the marker that later separated; the analysis adjusts for it. The subgroup results are post-hoc and are what the paper's conclusion rests on. Conducted at the laboratories of a cosmetics and health-food manufacturer, which employs every author. The framing ('potentially improves vascular health') runs ahead of a p of 0.097 on the endpoint the trial set out to measure.