Randomization and blinding
An allocation controller at Orthomedico Inc. (Tokyo, Japan) randomly assigned subjects to two supplementation groups (NMN or placebo) by block random allocation. The allocation ratio of each group was 1:1. An allocation table was created based on the algorithm of block random allocation. The allocation table contained the types of groups (NMN or placebo) and the identification code of each individual and was kept concealed using an emergency key by the allocation controller until the blinding review was completed. DHC Corporation provided the NMN and placebo capsules to the allocation controller. After making sure that the capsules were indistinguishable, the allocation controller assigned an identification code to all the capsules based on the allocation table. After the screening test, the capsules with the identification code was to subjects by a blinded investigator. Information on allocation was not opened until the subjects for analysis were determined at a clinical meeting after test completion.