The effect of habitual and experimental antiperspirant and deodorant product use on the armpit microbiome

Abstract

An ever expanding body of research investigates the human microbiome in general and the skin microbiome in particular. Microbiomes vary greatly from individual to individual. Understanding the factors that account for this variation, however, has proven challenging, with many studies able to account statistically for just a small proportion of the inter-individual variation in the abundance, species richness or composition of bacteria. The human armpit has long been noted to host a high biomass bacterial community, and recent studies have highlighted substantial inter-individual variation in armpit bacteria, even relative to variation among individuals for other body habitats. One obvious potential explanation for this variation has to do with the use of personal hygiene products, particularly deodorants and antiperspirants. Here we experimentally manipulate product use to examine the abundance, species richness, and composition of bacterial communities that recolonize the armpits of people with different product use habits. In doing so, we find that when deodorant and antiperspirant use were stopped, culturable bacterial density increased and approached that found on individuals who regularly do not use any product. In addition, when antiperspirants were subsequently applied, bacterial density dramatically declined. These culture-based results are in line with sequence-based comparisons of the effects of long-term product use on bacterial species richness and composition. Sequence-based analyses suggested that individuals who habitually use antiperspirant tended to have a greater richness of bacterial OTUs in their armpits than those who use deodorant. In addition, individuals who used antiperspirants or deodorants long-term, but who stopped using product for two or more days as part of this study, had armpit communities dominated by Staphylococcaceae, whereas those of individuals in our study who habitually used no products were dominated by Corynebacterium. Collectively these results suggest a strong effect of product use on the bacterial composition of armpits. Although stopping the use of deodorant and antiperspirant similarly favors presence of Staphylococcaceae over Corynebacterium, their differential modes of action exert strikingly different effects on the richness of other bacteria living in armpit communities.

Skin microbiota: Friend or foe in pediatric skin health and skin disease

“…The most commonly found viral families on adult skin include Cirocoviridae, Polyomaviridae, and Papillomaviridae . Body‐site specificity and stability are likely driven by innate skin characteristics including moisture, lipid content, pH, salinity, temperature, and environmental exposures including skin care products …”

“…Deodorant and antiperspirants impact bacterial diversity in the axilla . Habitual use of these hygiene products resulted in a bacterial community dominated by Staphylococcus , while non‐users were dominated by Corynebacterium .…”

“…42,45 Body-site specificity and stability are likely driven by innate skin characteristics including moisture, lipid content, pH, salinity, temperature, and environmental exposures including skin care products. 5,[46][47][48][49] When do these microbial communities stabilize? Six recent studies used next-generation sequencing to investigate evolution of the skin microbial community with age.…”

Towards a bacterial treatment for armpit malodour

“…For the general public, underarm cosmetics do the job of reducing bacterial growth and adding perfume and thus reducing underarm odour. Moreover, staphylococci can regrow the fastest when no more underarm cosmetics are used …”

The smell of us – crowdsourcing human body odor evaluation

“…This perception motivates the use of commercial antiperspirants and deodorants, which reduce body odor by suppressing sweat production or killing odor-causing bacteria (Urban et al, 2016). A large part of body odor research is focused on technical improvements to these products, motivated by a multi-billion dollar global market (Gilbert & Firestein, 2002).…”