A landmark international study has uncovered the strongest evidence yet that our genes—along with biological sex—shape how we experience smells, opening new possibilities for understanding brain health and personalized medicine. The research, conducted by the University of Leipzig and published on July 30, 2025, in Nature Communications, identified ten distinct regions of the human genome connected to the ability to detect specific odors. Remarkably, seven of these genetic links had never before been documented, while three regions proved sensitive to sex-specific factors such as hormones, helping explain why smell perception can shift during life events like menstruation or pregnancy.
For many in Thailand, where aromas permeate society—from bustling street food stalls to traditional herbal therapies—this study is more than scientific curiosity. It offers a window into why scents affect individuals in deeply personal ways and why certain odors may evoke powerful memories or trigger discomfort differently among people. The findings could also shape how medical professionals in Thailand use smell as an early screening tool for illnesses like Alzheimer’s disease, where early loss of smell has long been recognized as a subtle yet telling symptom.
The study’s significance lies in its scale and precision. By analyzing genetic material and olfactory abilities in more than 21,000 Europeans, researchers were able to pinpoint ten genome regions tied to particular scents. Seven of these regions had not previously been connected to smell, suggesting the human genome holds far more olfactory secrets than previously thought. Participants were tested on their ability to recognize twelve familiar odors using clinical scent pens, a process rigorously compared to their DNA profiles and analyzed across cooperating European studies. “We identified ten genetic regions associated with the ability to detect specific odours—seven of these are new discoveries. Three of the regions also show sex-specific effects, meaning they function differently in men and women,” said the lead scientist at the Institute for Medical Informatics, Statistics and Epidemiology at Leipzig University. Sex-specificity was particularly pronounced in certain genomes activated by androgens, hormones produced in different quantities in males and females and which fluctuate during reproductive cycles.
To everyday Thais, this helps explain why, for instance, some people may be more sensitive than others to the potent aroma of durian, or why certain culinary herbs spark intense reactions in different groups. Expert voices in the study emphasized that “women, for example, perceive smells differently during their menstrual cycle or pregnancy. These findings can support efforts to tailor medical diagnoses more closely to biological sex,” noted a medical faculty researcher involved in the research. Historically, olfactory loss or alteration has been seen in traditional Thai medicine as a potential warning sign of disease—this modern genetic evidence aligns closely with such ancient observations, now seen through the lens of contemporary science.
The research also sheds light on the broader role of olfaction as part of neurodegenerative risk. Importantly, the team uncovered a genetic association between odor detection and risk for Alzheimer’s disease, bolstering previous data that suggest loss of smell can be among the earliest signals of the condition. “There is a link between the risk of Alzheimer’s disease and the ability to detect odours. This strengthens the evidence that the sense of smell, sex hormones and neurodegenerative diseases are interconnected,” commented the study’s first author from the university’s Faculty of Medicine. In practical terms, this could mean that routine assessment of olfactory ability—an approach already used informally in some Thai clinical settings—could become a more targeted, scientifically grounded part of health screening, particularly for those with a family history of dementia.
Interestingly, the genetic connections discovered were specific to particular scents; there was no “universal smelling gene” affecting all odors. This finding suggests that people may have very different scent perception profiles depending on their particular combination of genetic markers. In a country like Thailand, known for its complex food aromas and diverse flora, this discovery may help explain ongoing debates about which smells are considered pleasant, medicinal, or offensive.
As is often the case, the study’s focus on Europeans opens important questions about scent genetics among Asian populations, including Thais. Genetic information varies globally, suggesting some specific odor-sensitivity genes identified in Europe may not be as prevalent or play the same role in Southeast Asia. However, the research methodology—large-scale, genome-wide association studies paired with odor identification tasks—lays a robust foundation for similar research in Thailand, where unique environmental scents and culinary traditions may have exerted distinct genetic pressures over generations. Such data would serve not just the medical field but also anthropology, history, and food science by unraveling the cross-cultural evolution of scent preferences.
The findings from Leipzig coincide with an even larger ongoing study in Germany, involving some 200,000 participants, aimed at understanding the interplay between genes, hormones, and the olfactory system. Should similar projects be developed in Thailand, they may aid in mapping the genetic roots of popular Thai scent profiles such as kaffir lime, lemongrass, or kaprao (holy basil). Partnerships between medical schools, scent laboratories, and culinary institutions could drive new research, further linking olfactory genetics to fields as diverse as tourism, education, and environmental monitoring.
Looking to the future, the practical impact of this genetic knowledge could be broad. Agents at Thailand’s public health agencies might integrate simple scent tests into routine screenings for at-risk populations, using the results to trigger earlier interventions for cognitive decline. Meanwhile, Thai perfumeries and the food industry may one day employ genetic insights to customize fragrances and flavors, appealing to individual scent profiles. Locally, sex-specific medical approaches could become more nuanced, taking into account how fluctuating hormone levels influence sensory health, particularly among women during pregnancy or menopause.
For now, Thai readers keen to take action can participate in local academic studies on smell and health, share family histories of olfactory loss with their doctors, and explore new ways to use the sense of smell as a barometer of well-being. Women experiencing sudden changes in smell during menstruation, pregnancy, or later life should mention these shifts to their healthcare providers, as they may hold key information about overall health. Both individuals and the Thai health community are encouraged to monitor further research on genetic and sex-based differences in scent perception, especially as global projects broaden to include diverse population groups.
For further reading and the detailed scientific findings referenced in this article, visit the publication on Neuroscience News and the original research in Nature Communications. For a summary of the study’s local and medical context, see the University of Leipzig’s official release.