When a discovery is made in the smell world, it doesn't make it to the top of your news feed. They're usually hard to explain in the first place, likely hard to discuss with your friends because we do not talk about smells to almost anyone, and the utility of these discoveries is pretty hard to predict, considering the world of smell is kind of frozen in time, like the time back when alchemy experiments were being funded by the Church. That being said, let's talk about smells for a minute.
Also, important note of interest - we're coming for your sniffing behaviors and I mean it.
Prototype device restores lost smell by teaching the brain to feel odors
Nov 2025, phys.org
Sensory substitution - They developed a system that captures odors using an artificial nose (e-nose) and translates that chemical information into a specific digital code. This code is then passed through an intranasal electrical stimulator (a small magnetic clip) placed on the septum, the wall separating the nostrils, to trigger the trigeminal nerve.The study authors tested their innovation on 65 people (13 with normal smell and 52 with smell loss) across four experiments. All were able to detect odorant molecules, and most could distinguish between two distinct odors. The device also worked just as well for patients who couldn't smell as it did for healthy people, meaning the trigeminal system is a reliable pathway for transmitting coded signals for everyone.
via Université Claude Bernard Lyon, CNRS, INSERM, Microsystems Laboratory at EPFL, Technische Universität Dresden: Halina B. Stanley et al, Substitution of human olfaction by the trigeminal system, Science Advances (2025). DOI: 10.1126/sciadv.adu7926
My GLP-1 Medication Changed the Way Perfume Smells to Me
May 2025, Allure via Monnel
Theory 1: Bad feedback - dissonance between the “feel-good neurotransmitters” of the brain — like dopamine and oxytocin — and my olfactory receptors, or what I’m smelling.Theory 2: Scent memory disruption - Then the brain “decodes” what it’s smelling, like Chanel No. 5 or a rotten egg, but the way you respond to a scent is totally unique. It “typically has to do with an association with memory”Theory 3: Scent aversion - “a population of neurons in the hindbrain [the lower part of the brain that connects it to the spinal cord] seem to play a key role in mediating the vast majority” of the appetite suppressant and weight loss effects of the GLP-1 drug.
Sexual selection: Human odor-based mating preferences do not guarantee gamete-level compatibility
Jun 2025, phys.org
https://phys.org/news/2025-06-sexual-human-odor-based-gamete.html
10 women first ranked the attractiveness and intensity of body odor samples collected from 11 men, followed by an analysis of whether female body odor preferences in these same 110 male–female combinations predicted sperm performance in the presence of follicular fluid. ... and women committed to testing their ovulation to ensure that odor rating occurred during their fertile window."Women showed a preference for the body odors of MHC-similar men. However, sperm from MHC-dissimilar men exhibited higher motility when exposed to female follicular fluid, suggesting that the most attractive males may not necessarily always be the most optimal partners in terms of fertilization success".The results indicate that individual and gamete-level mate choice processes may in fact act in opposing directions, and that gamete-mediated mate choice may have a definitive role in disfavoring genetically incompatible partners from fertilizing oocytes.
via University of Eastern Finland: Annalaura Jokiniemi et al, Female-mediated selective sperm activation may remodel major histocompatibility complex-based mate choice decisions in humans, Heredity (2025). DOI: 10.1038/s41437-025-00759-9
One of a kind: Humans have unique breathing 'fingerprints' that may signal health status
Jun 2025, phys.org
Scientists can identify individuals based solely on their breathing patterns with 96.8% accuracy.This high-level accuracy remained consistent across multiple retests conducted over a two-year period, rivaling the precision of some voice recognition technologies.These respiratory fingerprints correlated with a person's body mass index, sleep-wake cycle, levels of depression and anxiety, and even behavioral traits. For example, participants who scored relatively higher on anxiety questionnaires had shorter inhales and more variability in the pauses between breaths during sleep.
via Noam Sobel of the Weizmann Institute of Science: Humans Have Nasal Respiratory Fingerprints, Current Biology (2025). DOI: 10.1016/j.cub.2025.05.008.
Changes in female body odor during ovulation elicit measurable reactions in men, finds study
Jul 2025, phys.org
I was at first laughing because this was done in Japan and on Japanese women who tend to not have what most people call "body odor" due to the prevalence of the ABCC1 gene among the East Asian population, but then, direct from the article, "The odour emitted from the backs of women in the ovulatory phase increased testosterone secretion in men. The odour emitted from the chest reduced cortisol secretion in men."
via University of Tokyo: Human ovulatory phase-increasing odors cause positive emotions and stress-suppressive effects in males, iScience (2025). DOI: 10.1016/j.isci.2025.113087
Radio waves amp up smell without surgery or chemicals
Aug 2025, phys.org
Unlike traditional aroma-based therapy, which indirectly treats smell loss by exposing the patient to chemicals, radio waves can directly target the part of our brain responsible for smell, without causing pain.In the study, the team asked volunteers with a healthy sense of smell to sit while a small radio antenna was placed near, but not touching, their forehead. For five minutes, this antenna gently sent out radio waves to reach the smell-related nerves deep in the brain.Before and after the short treatment, the authors tested how well the patient could smell very faint odors, like diluted alcohol or fruit scents, using pen-shaped odor dispensers called Sniffin' Sticks. They also recorded the patients' brain signals to see how active their smell nerves were.The team found that their method improved subjects' sense of smell for over a week after just one treatment.
via Hanyang University in South Korea: Noncontact radiofrequency stimulation to the olfactory nerve of human subjects, APL Bioengineering (2025). DOI: 10.1063/5.0275613
While it may go unnoticed, loss of smell may linger for years after COVID-19
Sep 2025, phys.org
(They used UPSIT-Sniffin Sticks)
Led by the National Institutes of Health's RECOVER initiative and supported by its Clinical Science Core at NYU Langone Health, a team of researchers from across the country explored a link between the coronavirus that causes COVID-19 and hyposmia—the reduced ability to smell.The results revealed that 80% of participants who reported a change in their smelling ability after having COVID-19 earned low scores on a clinical scent-detection test taken about two years later. Of this group, 23% were severely impaired or had entirely lost their sense of smell.Notably, 66% of infected participants who did not notice any smelling issues scored abnormally low on the evaluation as well, the authors say. [Because people don't even know they can smell in the first place, this sounds crazy but unfortunately it's true - people born without the sense of smell tend to live several years, sometimes into adulthood, before ever realizing they have no sense of smell.]...60% of uninfected participants who did not report olfactory problems also tested poorly during the clinical evaluation. [Which is the upsit?]
via NYU Langone, Icahn School of Medicine at Mount Sinai, Howard University, Massachusetts General Hospital, University of Arizona: Olfactory Dysfunction After SARS-CoV-2 Infection in the RECOVER Adult Cohort, JAMA Network Open (2025). DOI: 10.1001/jamanetworkopen.2025.33815
(This is nuts) People's sniffing behaviors predict what they are smelling, study shows
Dec 2025, phys.org
NEMO - neural encoding models of olfaction dataset - 12,000 experimental trials during which three human participants were asked to smell 160 different odors inside an MRI scanner.Researchers found that sniffing behaviors contained enough information to decode the identity of odors. Moreover, perceptual properties of odors appeared to be reflected in subtle sniffing pattern variations.
via Dartmouth College, Northwestern University Feinberg School of Medicine: Vivek Sagar et al, The human brain modulates sniffs according to fine-grained perceptual features of odours. Nature Human Behaviour(2025). DOI: 10.1038/s41562-025-02327-x
Gut bacteria may influence social behavior through smell
Mar 2026, phys.org
When gut bacteria break down choline-rich foods, such as eggs and meat, they generate TMA as a byproduct. The body's liver then converts TMA (trimethylamine, smells like rotten fish, ask your UTI about that) into an odorless metabolite. But in adult male mice, testosterone suppresses the liver enzyme that typically neutralizes TMA, allowing it to accumulate in urine.When the researchers blocked gut bacteria from producing TMA, aggression dropped. When they restored the chemical, aggressive behavior returned.In another experiment, the researchers treated young mice, which typically do not exhibit aggression, with TMA. Adult mice responded by biting and fighting — treating the younger mice like rivals.
via Northwestern University: Annika Cichy et al, A microbiome-derived olfactory signal regulates inter-male aggression and social dominance in mice, Current Biology (2026). DOI: 10.1016/j.cub.2026.03.009.
