In a randomized, double-blind, placebo-controlled trial of 30 healthy volunteers, in each participant, one axilla was treated with zinc oxide and the other with a placebo for 13 days. The microbiota and skin pH were analyzed before and during treatment. In addition, at the final visit, participants judged their own axillary odor.
Zinc oxide decreased total bacterial growth; specifically that of the odor-producing Corynebacterium spp. and Staphylococcus hominis, despite an increase in skin-surface pH. Compared with the placebo, zinc oxide also reduced self-perceived malodor.