
The thought of earwax and body odor might invoke a nose crinkle, but that’s not their only commonality. Both are secreted by apocrine glands. People have also noticed a curious pattern—those with sticky, honey-colored wax often have smellier pits, while those with white-grey, flakier wax tend to smell less. Intrigued by these quirks, researchers dug into the genetics behind what makes earwax and body odor uniquely personal, and how their variations influence skin bacteria.
In 2006, scientists identified the culprit: the ATP binding cassette subfamily C member 11 (ABCC11) gene.1 A single base change—from a G to an A—determines whether a person has wet (GG or GA) or dry (AA) earwax. But that’s not all.
“Microbe composition in both earwax and armpits is influenced by human ABCC11 genotype,” said Julie Horvath, a primate comparative genomics researcher at the University of North Carolina at Chapel Hill.
The ABCC11 gene functions as a sweat courier. It produces a protein that delivers protein- and lipid-rich sweat molecules to the skin, creating a feast for bacteria, Horvath explained. As lipids break down, they release volatile compounds—the source of body odor. In people with dry ear wax, ABCC11 is non-functional; this starves some bacteria and greatly reduces the smell of sweat.

This genetic pattern also determines which skin microbes thrive. Chris Callewaert, a microbiologist at Ghent University, identified Staphylococcus and Corynebacterium as the two most abundant groups in the armpit.2 People with a functional ABCC11 gene tend to have higher amounts of Corynebacterium, which Callewaert described as the cause of “sour, musty, and even fecal-like odors,” whereas those lacking this genetic form have more Staphylococcus, which produces “more neutral odors.” However, other microbes can contribute to these unique scents.
In 2017, Horvath launched a citizen science Armpit and Earwax Microbe Project to characterize how genetic variations shape the skin’s microbial makeup. By sampling the local community, she found that individuals with certain genotypes share similar yet distinct microbes in their earwax and armpits. Early findings from the earwax microbiome suggest that earwax type correlates with the abundance of some clinically relevant microbes.
Yet, genetics is just one piece of the puzzle. Body odor and microbial makeup also vary based on gender, diet, age, immune health, and deodorant usage. What researchers know so far is just the tip of the Q-tip!
What makes you curious? Submit a question for us to answer in future “Just Curious” columns.
- Yoshiura K, et al. Nat Genet. 2006;38(3):324-330.
- Callewaert C, et al. PLoS One. 2013;8(8):e70538.