2.1. Study Design
We conducted a randomized, double-blind, placebo-controlled, parallel-group trial at a single site, the Fukuda Clinic in Osaka, Japan, with clinical support from Soiken Inc. (Osaka, Japan), a clinical research organization, between June 2021 and September 2022. The study complied with the ethical principles outlined in the Declaration of Helsinki. This study was approved by the Institutional Review Board of Fukuda Clinic (Review Number: IRB-20210619-3) and the Meiji Institutional Review Board (Review Number: 202). The study protocol was registered in the University Hospital Medical Information Network Clinical Trials Registry (ID: UMIN000044933), and all participants provided written informed consent.