Study design
Thirty-six healthy male and female subjects were enrolled in this randomized, double-blind, placebo-controlled, parallel study. Written informed consent was obtained from all subjects involved in the study. Subjects were randomly assigned to two groups by Orthomedico Inc. (Tokyo, Japan). Subjects visited the clinic in Tokyo, Japan, for laboratory tests and safety assessments at baseline prior to the initiation of the intervention. All results were reviewed by a physician. Subjects were provided with either NMN (125 mg/capsule) or placebo capsules in batches for 12 weeks, and one capsule was ingested twice a day after meals for 12 weeks. NMN capsules contained NMN, cellulose, silicon dioxide, and calcium stearate. In contrast, placebo capsules contained cornstarch, cellulose, silicon dioxide, and calcium stearate. After the 12-week intervention period, subjects returned to the clinic for laboratory tests and safety assessment. All the subjects were recruited between June 22 and July 7, 2021, and the last subject’s visit was on December 8, 2021. The study was completed after the last subject completed the last visit. The researchers involved in collecting and analyzing the results were not informed of the treatment conditions. We did not perform a follow-up analysis after terminating NMN supplementation. All the procedures in this study were approved by the DHC ethics committee on 04/08/2021 (No.202101). This study was conducted in accordance with the ethical principles that have their origins in the Declaration of Helsinki and its subsequent amendments, and was registered with the identifier UMIN000045205 on 20/08/2021 in the clinical trial registration system of the University Hospital Medical Information Network and met the criteria of the International Committee of Medical Journal Editors.