A woman’s scent may do more than linger—it can subtly affect how others feel and behave. In Japan, researchers found that changes in body odor during ovulation may influence men’s stress levels and how attractive they find women.
At the University of Tokyo, scientists studied scent compounds that increase during ovulation. They added these to sweat samples and gave them to men to smell. The men rated the samples as more pleasant and linked faces as more attractive. They also showed lower levels of amylase, an enzyme tied to stress, suggesting a calming effect.
Kazushige Touhara, a professor at the university, led the work. “We identified three body odor components that increased during women’s ovulatory periods,” he said. “When men sniffed a mix of those compounds and a model armpit odor, they reported those samples as less unpleasant, and accompanying images of women as more attractive and more feminine.”
The scents didn’t just change perception—they altered physical stress responses. “Those compounds were found to relax the male subjects… and even suppressed the increase in the amount of amylase (a stress biomarker) in their saliva,” Touhara added.
The team included researchers from the International Research Center for Neurointelligence. While the effects resemble pheromones, Touhara explained that the findings don’t prove humans have them. “We cannot conclusively say at this time that the compounds… are human pheromones,” he said. But the study suggests scent may quietly influence emotional and social behavior.
Uncovering the Hidden Signals
The idea that body odor might influence attraction isn’t entirely new. Earlier research had shown that men often found the scent of ovulating women more appealing. However, those studies stopped at observation. They did not identify the exact chemical compounds responsible for the changes. That’s where this new study broke ground.
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To pinpoint these mystery molecules, the scientists used a method called gas chromatography-mass spectrometry. It allowed them to separate and identify tiny particles in the sweat samples. This led to the discovery of three specific compounds that rose in concentration during ovulation. These compounds were later added to test samples used in the study with male volunteers.
Collecting the original sweat samples was anything but easy. “The most difficult part of the study was to determine the axillary (armpit) odor profile within a woman’s menstrual cycle,” said Nozomi Ohgi, the study’s first author and a graduate student in Touhara’s lab.
She added that organizing the schedule of over 20 women, all at different stages of their cycles, was a huge task. “We also needed to interview each participant frequently regarding body temperature and other indicators of the menstrual cycle in order to understand and track their status,” she said. Each woman needed to be tracked for over a month, which made the data collection phase long and meticulous.
Testing Without Bias
To make sure the results were scientifically sound, the team followed strict testing rules. Most important was the “blind” method, where the participants had no information about the purpose of the scent samples they were smelling. Some participants were even given samples without any added compounds, serving as a control group. This helped prevent outside expectations or bias from affecting the responses.
The idea of pheromones influencing human behavior often comes up in popular culture, from romantic comedies to perfume ads. But scientifically, pheromones are defined as species-specific chemicals that produce clear and predictable behavioral or physical changes in others of the same species. Touhara was careful to draw a line between the results of this study and that classical definition.
“We cannot conclusively say at this time that the compounds we found which increase during the ovulation period are human pheromones,” he said. “The classical definition of pheromones is species-specific chemical substances that induce certain behavioral or physiological responses.”
Since the team didn’t confirm if the body odors were species-specific, they stop short of calling the compounds true pheromones. Instead, Touhara referred to them as “pheromone-like compounds” because they caused real effects—changes in stress and attraction—even without fitting the full pheromone definition.
Looking Deeper into the Brain
What happens next for this line of research? The team wants to expand the study in several ways. They plan to include a more diverse range of people to rule out the possibility that genetic factors might have swayed the current results. They also want to dig deeper into the chemical structure of the identified compounds and figure out exactly how these molecules interact with the brain.
One area of interest is how these odors affect emotional processing. Since the scent compounds appeared to relax the male subjects and change how they viewed female faces, the researchers believe that the brain’s emotional centers may be involved. Future studies will likely use imaging tools to track which areas of the brain respond to the smells.
A Complex and Subtle Connection
So, what does this mean for how people connect? While the idea of pheromones in humans remains unproven, this study shows there may be subtle biological signals happening below our awareness. The odors from one person may be picked up by another, quietly influencing stress levels or attraction. These effects aren’t dramatic or cartoonish, as often shown in the media, but they hint at a deeper sensory exchange that still isn’t fully understood.
At the same time, the researchers stress the need for careful interpretation. Odor and its effects can be influenced by many factors—cultural, environmental, and biological. What’s clear is that there’s still much to learn about the hidden ways human bodies might communicate through scent. As Touhara and his team continue their work, they offer a reminder: chemistry isn’t just for the lab. Sometimes, it’s in the air around us—quiet, complex, and deeply human.
Research findings are available online in the journal iScience01348-3?_returnURL=https%3A%2F%2Flinkinghub.elsevier.com%2Fretrieve%2Fpii%2FS2589004225013483%3Fshowall%3Dtrue).
Note: The article above provided above by The Brighter Side of News.
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