Early research suggests deodorant could be making your armpits smell worse

Bad news - a new study suggests that antiperspirants and deodorants could be causing bad bacteria to take over our armpits, making them smell worse. But don't throw out all your products just yet, this is very early research.

Deodorants and antiperspirants are widely used to help reduce sweat and underarm body odour - but an early study suggests that the products could be having the opposite effect.

Researchers at the University of Ghent in Belgium were interested in how these products change our underarm microbes - better known as the bacteria that dwell in the “rain forests” under our arms - and so they asked eight test subjects to stop using deodorant or antiperspirant for a whole month. 

Another subject who did not regularly use either was asked to use deodorant for the month. The timeframe was selected because it takes around 28 days for a new layer of skin cells to form,Ross Pomeroy writes for Real Clear Science.

The armpit bacterial community of each subject was tested at the start and the end of the month, and the results showed clearly that each armpit ecosystem had been altered. As all armpits are unique, it was hard to quantify specific changes, but one clear trend was apparent - antiperspirant use was linked to an increase in Actinobacteria. This is the “bad” type of armpit bacteria that instigate noxious armpit odour.

The results were published in the journal Archives of Dermatological Research, and lead author Chris Callewaert told Real Clear Science that the aluminium compounds in antiperspirants, which can block pores to prevent sweating, may be to blame, by killing off “good” bacteria and allowing Actinobacteria to dominate.

But don’t throw out your products just yet. The study only involved a small sample size of nine people, so further research is needed before the results are confirmed. But this is the first study in the world to specifically look at the effect deodorant has on the diversity and abundance of armpit bacteria, and opens up new possibilities for future research on the topic. 

Specifically, Callewaert is interested in finding out how underarm bacteria transplants might help reduce body odour in people who have severe issues with it.

It’s still early days, but with more research scientists might finally be closer to solving one of the most frustrating everyday - how to stop BO.