I’ve been wondering about this for a while and decided to research it.
- Asymmetrical sweat glands distribution
- Arm pits have different sets of microbes
- The side which is more active is usually less stinky
Asymmetrical sweat glands distribution
One arm pit will usually have more sweat glands than the other and this will lead to you sweat more on one side. Although sweat itself has no smell, it reacts with the bacteria under your arm and produces an odor. Since one side is sweatier than the other, the stink will be more noticeable on that pit.
But — here’s a real shocker — sweat and other secretions don’t actually smell. Sweat, sebaceous, and apocrine glands secrete volatile organic compounds, and odors arise when these “VOCs” interact with bacteria on the skin, in hair follicles, and in the mouth.
Arm pits have different sets of microbes
What are microbes?
Microbe is a term for tiny creatures that individually are too small to be seen with the unaided eye. Microbes include bacteria (back-tear-ee-uh), archaea (are-key-uh), fungi (fun-jeye) and protists (pro-tists).
YourWildLife.org actually did a informal study to find out how does one’s lifestyle affect their armpits’ microbiome.
The picture below is a comparison between one of the participant’s left and right pits
It indicates that there is more microbes in the left pit. Since odor is produced only when sweat interacts with the microbes, having a different set of microbes (eg. different types of bacteria or amount) will give each of your pit an unique bouquet.
The side which is more active is usually less stinky
This is a personal theory of mine. When I had surgery on my right shoulder and had it in a sling for about a month, my right pit produced some serious funk. I think that the more active your arms are, the more the pits are able to “breathe” or air themselves out, thus helping to mitigate some of the stink.