Objectives　As oxidative stress is known to cause physical fatigue, antioxidants are potential candidates for anti-fatigue agents. Imidazole dipeptides, reported to have strong antioxidative effects, have been demonstrated to be effective against fatigue-induced decline in physical performance. Here, we investigated the effect of imidazole dipeptides-containing drink on feeling of fatigue from daily activities in healthy people.
Methods　207 volunteers participated in a randomized, double-blind, placebo-controlled clinical study. Subjects were randomly divided into three groups；and provided with imidazole dipeptides 200 mg/day（low dose）, 400 mg/day（high dose）, or placebo for 8 weeks. We evaluated the subjective sensation of fatigue primarily by the visual analogue scale（VAS）.
Results　The VAS score was significantly lower 2 to 8 weeks after administration in the imidazole dipeptides 400 mg group compared with that in the placebo group.
Conclusions　Imidazole dipeptides was also effective as well for the attenuation of fatigue from daily activities, most likely attributable to its antioxidant action. Imidazole dipeptides-containing drink can thus be considered as one promising candidate for anti-fatigue food.