Armpit Bacteria Transplants Could Save Us From Our Stink

For the record, Chris Callewaert doesn't stink. Though the post-doctoral researcher at the University of California dubs himself Dr. Armpit, and spends his time trying to find a cure for body odor, when I spoke with him at the Biofabricate conference in New York on Thursday, there were no malodorous scents to be whiffed.

But he told me his fascination in the subject was inspired by personal experience.

"I was quite anxious about people noticing or commenting on my body odor, although the only person who usually notices is yourself, but it does impact your life," Callewaert told me.

There are a few factors that contribute to body odor, but Callewaert's research has found that the types of bacteria that happens to set up camp in your armpit plays a significant role. Your sweat doesn't smell on its own, but when it's broken down by the bacteria that live in and on your skin, it can cause odors.

Using DNA sequences, Callewaert has identified types of bacteria that are more prolific in the armpits of people with low or normal body odor and the types that are more common in people with severe body odor. A higher population of Staphylococcus epidermidis was associated with neutral pits, while a high concentration of Corynebacterium tended to cause more stench. In simple terms, the more good bacteria you have, and the less bad bacteria, the better you'll smell. But how do you get the good bacteria to move in and the bad bacteria to pack its bags? A bacteria transplant, of course.

Callewaert first conducted a successful armpit bacteria transplant back in 2013, with a pair of identical twins. One twin suffered from more severe body odor than the other, but once Callewaert and his team deposited good bacteria from his brother's pit, his odor improved, and it stayed improved. Since then, Callewaert has done 18 additional transplants with similar, though not as long-lasting results. Though these findings have not yet been published in a peer-reviewed journal, Callewaert told me they will be published in the coming months.

"It's not perfect yet," Callewaert told me. "Definitely, in the short term, it's very successful but people want to be helped for the long run. So we want to optimize the procedure."

It may seem like a frivolous problem to be solved, but research on armpit bacteria contributes to the growing understanding of the human microbiome—the unique interactive population of bacteria that live on and inside the human body—and how it impacts our health.

And for individuals who have serious body odor, a medical condition called bromhidrosis, it can be a debilitating problem. Callewaert said he's heard from patients who lost jobs because of their natural odor, or dropped out of school.

"They've lost their partners. They've lost their confidence. They've lost their friends. It really impacts their life," Callewaert said. "And it's such a taboo. People just think, 'why don't you use deodorant?' They actually wash themselves more than the average people and change their clothes more often. They're always anxious and that's why I want to help."

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