Individual comparisons of the levels of (E)-3-methyl-2-hexenoic acid, an axillary odor-related compound, in Japanese.

The (E)-3-methyl-2-hexenoic acid (E3M2H), an axillary odor-related compound, is known to occur in Caucasians. The aims of this study were to clarify whether E3M2H contributes to axillary odor in Asians and to quantify and compare individual levels of E3M2H. Quantitative determination of E3M2H was performed by means of gas chromatography-mass spectrometry of sweat extracted from the axillary areas of T-shirts worn for 24 h by Japanese subjects. The amount of E3M2H was 15.9-34.6 nmol/ml in six of 30 subjects. Our method succeeded in quantitative analysis of E3M2H from axillary sweat collected individually; we also showed that E3M2H could be detected in Asians. This is the first report in which the amount of E3M2H in axillary sweat was quantified on an individual basis and compared to reveal individual differences. The results of this study indicate that E3M2H might contribute to axillary malodor in Asians as well as Caucasians.