Human axillary odour is commonly attributed to the bacterial degradation precursors in sweat secretions. Age, sex, genetic factors, environmental factors, hygiene and the use of cosmetics may contribute to body odour by influencing the quantity and quality of secretions or types of bacteria present on skin.
In our society, people are more and more concerned about their personal hygiene and the use of underarm cosmetics is common practice to obtain better body odour or prevent excessive sweating: deodorants are important for social confidence and to improve the quality of life, too.
Axilla microbiota
The microbial community of the human axilla plays a key role in the formation of axillary odour by biotransformation of odourless natural secretions into volatile odorous molecules.
The axillary region is a specific habitat and differs significantly from other body parts because it harbours hair follicles with sebaceous glands and a high density of sweat glands. In this environment Corynebacteria spp. (belonging to Actinobacteria phylum) and Staphylococcus spp. (belonging to Firmicutes phylum) dominate the resident flora.
The microbial biotransformation of secreted nutrients in the human axilla leads to the development of characteristic and individual odour profiles. Sweating is both healthy and natural and human perspiration is actually odourless, but when bacteria on the skin come in contact with sweat dripping from the pore, they cause body odour.
In the studies, our researchers have demonstrated that axilla microbiota analysis by MALDI/TOF is a powerful tool for assessing the efficacy of deodorants. In particular, following the behaviour of microbiota upon treatment, it has been possible to determine if indeed a product is active against odour forming bacteria and hence it can help with reducing/controlling sweat odour.
