Key Questions Answered
Q: What did the study find about female body odor during ovulation?
A: Researchers identified three volatile scent compounds that rise during ovulation and, when blended into model armpit odors, made those samples smell more pleasant to men. Men who smelled these samples also rated the faces paired with the scents as more attractive and more feminine.
Q: Did these compounds affect male physiology or emotions?
A: Yes. Men exposed to the ovulation-linked scent mixture reported feeling less stressed and showed reductions in salivary amylase, a physiological marker associated with stress.
Q: Are these compounds proven human pheromones?
A: Not conclusively. The results point to pheromone-like effects on perception and physiology, but they do not satisfy the strict, species-specific definition required to confirm human pheromones.
Summary: Specific scent compounds in female body odor increase around ovulation and can subtly influence male perception and stress. When these compounds were added to armpit odor models, men judged the odors as more pleasant and found associated female faces more attractive and feminine. Physiological measures also indicated a calming effect, suggesting body odor may unconsciously shape social and emotional interactions between men and women.
Key Facts:
- Ovulatory signals: Three volatile compounds increase during the ovulatory phase and alter male perception.
- Emotional and physiological effects: Exposure to these scents reduced reported stress and lowered salivary amylase, while increasing perceived attractiveness.
- Pheromone status: Findings are consistent with pheromone-like influences but do not establish species-specific human pheromones.
Source: University of Tokyo
Overview of the study
Researchers at the University of Tokyo, from the Department of Applied Biological Chemistry and the International Research Center for Neurointelligence (WPI‑IRCN), investigated how changes in female axillary (armpit) odor across the menstrual cycle influence male perception and physiology. Building on earlier work that reported menstrual-cycle-dependent shifts in body odor pleasantness, the team set out to identify the specific volatile compounds responsible and to test their behavioral and physiological effects on men.
Using gas chromatography–mass spectrometry to perform detailed chemical profiling, the researchers tracked volatile compounds from axillary samples collected at multiple time points across participants’ menstrual cycles. They identified three compounds that consistently rose during ovulation. To test their effects, the team created a model armpit odor and added a mixture of the ovulation‑elevated compounds, then evaluated how male participants responded to these modified odors compared with controls.
Men rated the odors with the ovulatory compounds as less unpleasant, and they gave higher attractiveness and femininity ratings to faces that were paired with those odors. Importantly, these perceptual changes were accompanied by measurable physiological shifts: exposed men reported lower stress and showed suppressed increases in salivary amylase, a recognized stress biomarker. Together, the findings indicate that ovulation-associated odor components can produce both subjective and objective calming effects in male receivers.
Experimental design and challenges
Collecting reliable axillary odor samples across menstrual cycles required careful scheduling and extensive participant monitoring. The lead researcher noted the logistical burden of coordinating over 20 women so odors could be gathered at key cycle stages. Participants were interviewed frequently about body temperature and other cycle indicators to ensure accurate timing, and sample collection took over a month per individual in many cases.
To minimize expectation effects, the study was conducted blind: male raters were not informed about the scent conditions or the study aims. Some participants received control stimuli with no added compounds to serve as baselines. These precautions reduced the influence of conscious bias and strengthened the behavioral and physiological comparisons.
Interpretation and limits
The authors caution against interpreting the results as proof of human pheromones. By classical definition, pheromones are species-specific chemicals that trigger innate behavioral or physiological responses across individuals of that species. This study demonstrates that certain ovulation-associated compounds influence male perception and stress, but it does not establish species specificity or the complete signaling pathway required to label them as pheromones. The team therefore describes the substances as pheromone-like until further evidence clarifies their status.
Next steps
Planned follow-up work includes expanding participant diversity to rule out genetic or population-specific effects, performing deeper chemical characterization, and using neuroimaging to examine how these odors affect brain regions involved in emotion and perception. These future studies aim to detail the mechanisms by which ovulatory odors modulate social impressions and physiological states.
Funding: Supported by the ERATO Touhara Chemosensory Signal Project (JPMJER1202), JST Mirai program grants (JPMJMI17DC, JPMJMI19D1), JSPS KAKENHI grants (18K14651, 22K06418, 21K13546, 18K02477, 18H04998, 21H05808, JP18H05267, JP23H05410) and a Grant for Women Scientists in Challenging Research from the Japan Society for Bioscience, Biotechnology, and Agrochemistry.
Patent application: A patent application has been filed under PCT Application No. PCT/JP2024/024888, based on results from this study.
About this olfaction and behavioral neuroscience research news
Author: Rohan Mehra
Source: University of Tokyo
Contact: Rohan Mehra – University of Tokyo
Image: Image credited to Neuroscience News
Original Research: Open access. “Human ovulatory phase-increasing odors cause positive emotions and stress-suppressive effects in males” by Kazushige Touhara et al., published in iScience. DOI: 10.1016/j.isci.2025.113087
Abstract
Human ovulatory phase‑increasing odors cause positive emotions and stress‑suppressive effects in males
Olfactory cues play a crucial role in many animals for signaling sex, kinship, and reproductive state. In humans, previous work has suggested men find female body odor more attractive around ovulation, but the molecular and physiological bases have remained unclear. Combining sensory evaluation with gas chromatography–mass spectrometry, this study identified volatile compounds that change across the menstrual cycle. Three compounds that rise during ovulation reduced the unpleasant qualities of baseline axillary odor, making ovulatory-phase odors appear most pleasant to male raters. These compounds also reduced hostility and stress reactions to the baseline odor, promoting relaxation and improving the positive impression of female faces. The results support the idea that several ovulation-associated odorants contribute to positive effects of ovulatory female scent on male perception and physiology.