Studies show millions of Americans throw away money on deodorants. Anyone who’s been on a crowded bus recently may question whether the money is being thrown away—one in 20 people who do need deodorant nonetheless decline to avail themselves of it—but researchers say that two percent of people carry a gene variant that results in no underarm odor at all. The same study found that nonetheless, 78 percent of the people with that variant use deodorant anyway. Some of these people use it simply as an antiperspirant to avoid the feeling of excessive perspiration, but the researchers speculate that in most cases, people use deodorant because using deodorant is normal, and not because they believe, or even think about, whether they need it.
The gene is called ABCC11, and it produces a protein that is important in metabolism and in distributing nutrients and other compounds throughout the cells of the body. The protein associated with ABCC11 is one of the most important in not just humans but all life. In addition to life functions and sweat odor, ABCC11 determines the color and consistency of earwax. People with the version that makes their sweat odorless also have dry earwax. The variant doesn’t do any harm, it only affects earwax and perspiration; the gene is not known to be associated with any diseases.
For people who do have odoriferous sweat, the scent can provide a wealth of information about what’s happening in the body. Your body produces perspiration as a cooling mechanism, and there is evidence that it carries pheromones which are an aspect of human social behavior—not as important as in other large mammals, but more important than had previously been suspected.
That means that changes in body odor aren’t always simply ordinary changes in body output. Sometimes these changes simply reflect diet—spicy foods, onions, and garlic don’t merely lend their odor to the eater’s breath, it also comes out in sweat, particularly armpit sweat. Eating lots of red meat makes people smellier in both senses of the word. Hormonal changes, such as due to pregnancy, not only make you better able to pick up scents around you, they can alter your own. Even changes in mood might be reflected in body odor, some scientists suggest.