To evaluate the impact of coenzyme Q10 (CoQ10) intake on body odor, two studies that focused on 2-nonenal contained in the gases emanated from the skin were conducted. The first study targeted 20 healthy women aged 65–74 years in a placebo-controlled cross-comparison study. Subjects were divided into two groups using blood CoQ10 concentration as an index, with ubiquinol (QH) or placebos administered every 4 weeks (5-week washout). On measuring concentrations of CoQ10 in blood and 2-nonenal in skin gas before and after continuous use, CoQ10 level of QH intake group increased significantly, whereas 2-nonenal level reduced significantly. In the second study, 24 healthy women aged 65–74 years were divided into four groups. QH, ubiquinone, vitamin E and placebos were administered in 4 weeks, and each concentrations of 2-nonenal in skin gas were measured. QH and ubiquinone reduced 2-nonenal in skin gas; however, changes in vitamin E were not observed. Therefore, CoQ10 intake reduced 2-nonenal emanation from the body.