The Joy of Scents

Smelling a happy person may make you happy.

sweaty man
Oozing happiness from every pore.

Mike Watson Images/moodboard

“By being a guy’s best first move … Axe is designed to keep guys a step ahead in the dating game,” boasts Unilever, the company that sells Axe products. Of course, if you don’t happen to be a gullible 13-year-old boy, you probably don’t believe that body spray or deodorant is a magic elixir with the power to turn nice girls naughty. But what if it were possible to change a person’s mood with just a scent? The idea may not be that far-fetched, according to a new study in the journal Psychological Science—reporting work that was funded by Unilever. The study found that it might be possible to subconsciously trigger a state of happiness using the scent of—deep breath now—human sweat.

People send all kinds of secret messages through their secretions. When smelling chemicals in male sweat, women become more alert, and they can even tell whether that sweat was made by a guy who was particularly turned on. (Cautions the New York Times: “No man should imagine that based on these conclusions he can improve his sex life by refraining from bathing.”) But until now, most sweat studies have focused on sexual arousal or negative emotions like fear. For obvious reasons, these emotions are crucial to survival and evolutionary success. If your friend spots a puma, it may be helpful for you to be able to sniff out instant cues to be on the alert or flee for cover.

Being able to transmit positive emotions may also have a profound social impact, says Gün Semin, a psychologist at Utrecht University in the Netherlands and lead researcher on the study. After all, “the pursuit of happiness is not an individual enterprise,” as he and his fellow researchers write rather eloquently in the new study. So Semin’s team decided to test whether people could communicate happiness via sweat.

First, the researchers needed to make some sweat. They had 12 sweater-clad male participants refrain from sex and garlic and shave their armpits (apparently a tall order, as three failed and their sweat had to be discarded from the study) and placed them in a dark, warm room. Over three sessions, each man sweated into sterile pads while watching one of three types of videos: happy-inducing (the Bear Necessities singalong from Disney’s The Jungle Book), fear-inducing (The Shining), or neutral (weather forecasts).

Next, 36 lucky ladies had the honor of getting to sniff each type of sweat while researchers monitored their facial movements. After each sniffing, they were given a cognitive test and a self-assessment on the “pleasantness and intensity” of the sweat they had smelled. The study was triple-blind, meaning neither the researchers nor the participants knew what kind of sweat they were smelling, nor did the researchers analyzing the data.

Remarkably, the women reacted differently to each type of sweat, the researchers found. When the women smelled the “happy sweat,” they displayed the physical markers that reflect a state of happiness, including a “Duchenne smile”—a smile that extends all the way to your eyes, as opposed to the fake grin known as a Pan Am/Botox/Joan Harris smile. They also displayed a broader thought processing style, reflective of a positive mood.

Advertising gets at you through your senses. Commercials worm their way into your psyche with nostalgic jingles. Fast-food restaurants entice you with huge photos of gleaming burgers and bold hues that say, “quick, eat here!” But what if companies could manipulate you with an aroma? “If we can actually extract the biochemical combination that is induced by happiness, then you can have products that are ‘laced’ with this biochemical and will make people feel more positive,” says Semin, who is also the director of the William James Center for Research in Lisbon, Portugal.

The possibilities are wide-ranging—and a little scary. Need to calm down an angry mob? Forget tear gas and try blasting them with a haze of happy human sweat. Want to make sure everyone at your party has an amazing time? Stick some sweat in the fog machine. Feeling blue? Just spritz it on for an instant mood lift—it’s like Prozac in an aerosol can! Of course, in reality, the effects are a bit subtler: “It’s not going to kick you off your feet and suddenly you’re in seventh heaven,” says Semin.

Moreover, mimicking human sweat for commercial use would be massively difficult. First, researchers would have to parse out its unique chemical cocktail from among the 180 to 200 known chemicals that make up human body odor. That’d be like determining Coca-Cola’s proprietary formula from scratch. “It’s almost like a chemical barcode,” says Johan Lundström, an associate professor of clinical neuroscience at the Karolinska Institute in Sweden, who researches how the brain processes chemical signals. “It would be enormously difficult to identify the patterns.” It would also be crucial for researchers to make sure they’re getting a clear signal across many sniffers because people tend to associate certain scents with memories that have their own personal history.

But, with enough time and money, it would be possible, says Lundström. In fact, researchers have successfully synthesized the mixture of two compounds that convey stress and anxiety to rats. But who would have that kind of time and money? Well, for instance, Unilever. Are you finding yourself in a great mood on a date even though the guy’s a jerk? Better ask him what deodorant he’s wearing.