Suppression of axillary odor and control of axillary bacterial flora by erythritol

Background: Erythritol is a sugar alcohol with 4 carbon atoms that has approximately 75% of the sweetness of sucrose. It is a safe and widely used food component. Aims: We herein investigated the growth inhibitory effects on axillary odor-causing bacteria and axillary odor-reducing effects of erythritol. Methods: Growth tests in vitro were performed on Corynebacterium minutissimum, C. striatum, and Staphylococcus epidermidis. An axillary odor sensory test and axillary bacterial flora analysis were then conducted. A test product containing erythritol was applied to the axillae of 18 subjects. Results: Erythritol significantly inhibited the growth of tested bacteria. The results of the axillary odor sensory test showed that the median values for each odor intensity of Total axillary odor intensity, Animal, Milk-fat, Damp-dried dust cloth, and Sourness were significantly lower in the test product application group than in the placebo group (p = 0, 0.008, 0.025, 0.004, 0, 0.001, respectively). The axillary flora analysis revealed that the relative abundance of the most dominant bacteria was lower in the test product application group than in the placebo group. Furthermore, the diversity of the total bacterial flora was significantly higher in the test product application group (p = 0.048). Conclusion: The present results suggest that erythritol inhibits the growth of the predominant bacteria in the axilla, increases the diversity of the bacterial flora, controls the bacterial flora of the skin to a healthy abundance ratio, and reduces axillary odor.