During the hot summer season, many people are concerned about the body odor excreted from their sweaty armpits. This is a common worry for South Koreans as well during summertime.

The mystery of why many Koreans don't have prominent armpit odor has piqued considerable interest in Korean online communities. There have been various online community posts that share topics and questions such as "My husband is Korean and he doesn't need to use the deodorant because he doesn't have the armpit smell," and "Why don't Korean people have the armpit smell?"

Past studies have identified a unique genetic trait among Koreans that makes them less susceptible to producing armpit odor. Research from the University of Bristol, utilizing data from the Allele Frequency Database (ALFRED) developed by Yale University, reveals that the majority of Koreans do not possess the ABCC11 gene, which is associated with armpit odor production. While more than 80% of Europeans, Africans, and Latin Americans carry this gene, it's infrequent among East Asians. Notably, Koreans stand out even among East Asians as only 0.006% of Koreans possess the ABCC11 gene, compared to 20% of Japanese and roughly 10% of Chinese populations.

Ian Day, a genetic epidemiologist at the University of Bristol who published a paper about the ABCC11 gene on LiveScience, stated, "The ABCC11 gene is basically the single determinant of whether you do produce underarm odor or not. The research showed that while only 2 percent of Europeans lacked the smelly gene, most East Asians and almost all Koreans lack this gene."

Korean netizens were fascinated by the study and commented, "That's interesting," "I want to know more in detail about this, this is interesting," "But then, what about the smelly people in the subway?" "There are Korean people who still smell if they don't wash," "I remember being shocked by westerners' armpit smells when I was overseas," "Am I not Korean then?" "Well, foreigners say we smell like garlic..." "Maybe I'm not Korean...I smell," "There's even a saying that Korean people are so odorless that they just smell like the food they ate," "I think we still have a smell but it's not as bad as others," and "I never knew what that armpit smell was until I went overseas and the foreigner sitting next to me on the plane had the nasty armpit smell."