A new study has come to some surprising conclusions about what happens when you swipe your armpit with some deodorant.

Julie Horvath, an evolutionary genomicist who also tracks the human genome and that of primates, wanted to know what happened to the bacteria culture located in our pits, and found that using deodorant and antiperspirant drastically altered it, according to a Washington Post report.

Horvath said she is interested in armpits because they hold many of the keys of primate and human evolution. They are shielded from the elements and thus can freely grow and multiply, and they are the main cause of body odor, which has implications for mating.

Her findings, published in the journal PeerJ, involved looking at microbes in the armpits of 17 individuals. They were divided into three groups: antiperspirant users, deodorant users, and a group that didn’t use anything. Then, their pits were swabbed twice a day.

The scientists then took to examining the swabs and analyzing the DNA. And what they found was qutie interesting.

The researchers found that the microbe colonies in our armpits are quite susceptible to products use on them. The antiperspirant users found that their microbe colonies almost entirely disappeared. Deodorants surprisingly didn’t have much effect on the microbe colonies, although most people mistakenly call antiperspirant, deodorant.

The reason antiperspirant deals a deadly blow to microbe colonies is it blocks sweat glands, versus deodorants, which simply masks the stink.