Deodorants, antiperspirants alter helpful skin bacteria

New research finds that antiperspirant and deodorant can significantly influence both the type and quantity of bacterial life found in the human armpit’s microbiome.

“Thousands of bacteria species have the potential to live on human skin, and in particular in the armpit”, said ecologist Rob Dunn from North Carolina State University. Researchers said further study is needed to determine if this disruption has dire or beneficial effects.

“Within the last century, use of underarm products has become routine for the vast majority of Americans”, says Julie Urban, co-author of the paper, assistant head of the genomics and microbiology laboratory at the NC Museum of Natural Sciences, and adjunct professor of entomology at NC State.

The researchers recruited 17 participants to the study; seven wore antiperspirants, which reduce sweating; five used deodorant, which kill odor-producing microbes; and five did not use either. On the first day of the study, they took samples from participants’ underarms to get a baseline of their typical microbial community.

“We know that these skin microbes interact with the immune system”, said Horvath reported by HealthDay, via Philly.com. “Just which of these species live in any particular armpit has been hard to predict until now, but we’ve discovered that one of the biggest determinants of the bacteria in your armpits is your use of deodorant and/or antiperspirant”.

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 antiperspirant users found that their microbe colonies nearly entirely disappeared.

They ran this study over a period of eight days, during which the researchers asked the participants to follow their normal hygiene on the first day and from days 2-8 they changed their routine according to certain variables. One group had three men and four women who were regular users of antiperspirant; another group of three men and two women were regular deodorant users; and the third group of three men and two women did not use either. Most surprising, however, was that the armpits of the three groups remained strikingly different after all participants went product-free for five days.

Corynebacteria are partly responsible for body odor, Horvath said, but they also help defend the body from harmful bacteria.

Staphylococcaceae are among the most common bacteria on human skin. Is it beneficial? Is it detrimental?

But the fact that the products we use can so dramatically alter the composition of these bacteria in our armpit microbiome could potentially have significant consequences, the researchers report in PeerJ. “Wearing a product does affect the microbes under your arm, but what those short and long-term consequences are, we don’t really know yet”.

It is perhaps important to mention that in 2014 there was another study released, which showed that bacteria present on our skin is actually beneficial, considering that it can lead to wound healing.