Ethics approval and consent to participate
The study was approved by the Graduate School of Medicine and Faculty of Medicine, University of Tokyo Research Ethics Committee (2018013P) and registered as “Randomized, double-blind, placebo-controlled parallel-group comparative study to evaluate the effect of nicotinamide mononucleotide (NMN) on the body composition in elderly persons” at UMIN-CTR (UMIN000036321). All participants provided written informed consent to participate in the study.