2.1.1. Study 1
Participants visited the study facility on the first test day. After a health check, the Profile of Mood Status 2nd edition for adults (POMS 2) [The animal study indicated that the positive effect of REP hydrolysate might be observed in a short time. Namely, the administration of REP hydrolysate shortened the immobile time on the tail suspension test by 5 min after a single oral administration. Furthermore, a previous clinical trial (Clinical Trial Registry No. UMIN 000041724) indicated that REP hydrolysate single intake induced a strong effect size of d = 0.8 in inter-group comparison on the Euthymia Scale change. Thus, Study 1 was designed to see whether a single intake of REP hydrolysate had an influence in humans. 