Does deodorant affect your underarm microbiome?

Woman Underarm Deodorant

Whereas we once viewed bacteria as the enemy of good health, we now know that the relationship we have with the bacteria that live on and in us, our microbiome, is much more complex. With many species playing a crucial role in our health.

A new scientific study was recently published that put forth the claim that “use of certain products like deodorants or antiperspirants fundamental effect are microbiomes”.

While the paper doesn’t put forth whether that change is good or bad (or neither), that hasn’t stopped others from making those leaps for them. Using the paper as “evidence” that we should all ditch deodorants and let our natural odors fly.

As a frequent rider on public transport, I think I speak for us all when I say this isn’t something any of us really wants. So, are all the body odor bloggers to be believed, Are we doomed to a life of stinky, sweaty pits?

Luckily, we don’t have to take anyone’s word for it. We can simply read the paper The effect of habitual and experimental antiperspirant and deodorant product use on the armpit microbiome on PeerJ. Something I strongly encourage you do whenever any blog or magazine talks about a “new scientific study”.

What did they do:
18* participants were divided into three categories: people who wear antiperspirants, people who wear deodorant, and people who don’t wear any underarm product at all. And then were told to stop using any product for a week. [*18 is a very small sample size, especially for something as varied as the microbiome]

What did they find:
“Here we experimentally manipulate product use to examine the abundance, species richness, and composition of bacterial communities that recolonized 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.”

In other words, products designed to stop the growth of odor-causing bacteria stopped the growth of odor causing bacteria.


Figure 1: Mean composition and richness of bacterial OTUs for all three product user types, combined OTU data from two and five days after stopping product use.

The more interesting result is that those who used products had more diverse microbiome’s that largely contained species of Staphylococcaceae while those who didn’t were largely Corynebacterium(aka the odor causing species’).

Now, the important question…Does this mean deodorant/antiperspirants are bad? The frustratingly unfulfilling but true answer as with most scientific studies is… “Not enough information, needs more research”. This paper is just a very small piece of a much bigger puzzle.

Or in the paper’s authors words:

Whether these species may interfere with the function of beneficial skin symbionts, contribute antibiotic resistance genes, prove benign, or perhaps even confer beneficial effects to human health remains an intriguing avenue for further study.

Trying to identify the role and specific effect of species in our microbiome is exceedingly difficult. Often in studies, people displaying the exact same distribution of species will have completely different outcomes. And as anyone who has suffered from a genetic or bacterial disease can attest, the historically “natural” biology is not always the healthy option.

The moral of the story…don’t be so quick to react based on what you read online 😉

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