Using deodorants and antiperspirants may help keep you feel fresh and dry all day, but these underarm products may also disrupt the bacterial community in your skin.
According to a new study published in the journal PeerJ on Feb. 2, the type and quantity of bacteria species that reside in your skin, particularly in the armpit, is influenced by the use of deodorant or antiperspirant.
For the research involving 17 individuals, researchers found that the antiperspirant users were likely to have far fewer bacteria compared with those who did not use any underarm products. The deodorant users were observed to have the most bacteria.
Study author Julie Horvath, from North Carolina Museum of Natural Sciences, said the difference is not surprising because deodorants have antimicrobial ingredients that fight odor. Antiperspirants prevent sweating and bacteria feed on sweat.
When all of the participants did not use either deodorant or antiperspirant by day two until day six, the researchers observed that they had similar amounts of bacteria in their armpit albeit the type and diversity of these bacteria differ.
Horvath's team observed that in participants who did not use any underarm product, 62 percent of their bacteria belonged to a group called Corynebacteria, which can cause body odor but provide defense against pathogens, and 21 percent were Staphylococcaceae bacteria, which are considered beneficial but may also pose risks to human health in some instances.
This pattern was reversed among participants who typically use antiperspirant or deodorant. Their bacteria were found to consist of 60 percent Staphylococcaceae bacteria and 14 percent odor-causing bacteria.
"Collectively these results suggest a strong effect of product use on the bacterial composition of armpits," Horvath and colleagues wrote in their study. "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."
While the findings of the study provide evidence of how underarm products can have an impact on the bacteria in the skin, these do not suggest people should start ditching their deodorant or antiperspirants.
The researchers themselves said that it is not yet clear if the disruption in the body's bacteria could have dire or beneficial effects.
"Within the last century, use of underarm products has become routine for the vast majority of Americans," said study co-author Julie Urban from North Carolina Museum of Natural Sciences. "Yet, whether use of these products favors certain bacterial species – be they pathogenic or perhaps even beneficial – seems not to have been considered, and remains an intriguing area needing further study."
