When I started taking a GLP-1 medication in October, I knew it would probably change a few things—our weekly dinner plan, how my pants fit, my relationship to alcohol (initial research shows low-dose GLP-1 drug patients drink less of it). What I didn’t know was that it would make me hate some of my favorite perfumes.
I’m a huge perfume lover and have over 100 bottles in my collection, which I’ve been adding to since high school. If I don’t wear perfume, I feel naked. Chypres—with their vintage-y blend of citrus, floral, and oakmoss notes—like Le Labo’s Ylang 49 are my favorite, but I dabble in almost every category. At least, I did—until I started injecting myself with a semaglutide once a week, beginning in October 2024.
At first, I felt totally normal. Granted, I was on a teeny-tiny dose of GLP-1 drug, the massively popular medication that mimics our bodies’ own GLP-1 hormone. (This hormone is naturally found in the gut, helps regulate blood sugar, and tells you when you’re full; it communicates with hormone receptors all throughout the body, including in the brain.) As I upped my dosage of a compounded semaglutide (meaning, it’s made and sold directly by licensed pharmacies) over time, going from five to 10 to 20+ units, I’d feel nauseous for a few days post-injection. It interrupted my daily routine, especially when traveling by car or airplane, and led me to purchase an herbal anti-nausea spray for on-the-go relief. It also messed with the way I smell perfumes.
Suddenly, anything that smelled remotely sweet or edible made me want to hurl. I’ve always loved a good vanilla fragrance; Atelier Cologne’s Vanille Insensee was a signature scent for years and a forever favorite, even if they no longer sell it in the U.S. (I have a stash hidden in a cool, dark place under my bed.) But just thinking about these scents had my stomach churning—even writing about these scents makes me queasy.
Gourmands (fragrances with food-inspired notes like caramel) provoked the most dramatic reaction, but I also had a hard time with musky scents, anything with fig, and certain floral notes. Instead of smelling soft or soapy, musks smelled metallic, like the rubbing alcohol pads I use prior to each GLP-1 injection. The creaminess of fig seemed amplified until it was sickeningly sweet, and certain floral notes, like tuberose, suddenly felt very heavy and sticky. It got to the point where testing a new fragrance—which I do quite a bit for my job as a beauty writer—made me nervous. I’d hold my breath and wait as long as I could before inhaling. It felt a lot like the early months of pregnancy, when I would suddenly recoil from something I previously enjoyed. (My son is four and I still can’t eat fried chicken.) I found myself gravitating toward light, “easy” florals, which in the “before times” would have made me snobbishly turn up my nose in favor of something grander.
For someone who has always loved perfume and makes some of her living writing about perfume, this was kind of a big deal. It’s hard when something you love suddenly turns on you! So as more and more friends began taking GLP-1 drugs, I did a little investigative journalism regarding their side effects, to see if what I experienced was happening to other people I knew, too. What I’ve found is that my friends’ experiences are all over the map; a few had intense nausea each time they went up a dose, sometimes so bad they were bedridden for a day. Others had digestive issues that required a daily dose of Metamucil powder, and some had no side effects at all. But no one I surveyed had the same scent-related aversions as I did. Thus, I went where curious folks often go: Reddit. There, I found that many GLP-1 medication users on the /fragrance board had the exact opposite experience: they wanted to wear gourmand scents or found themselves “ravenous” for fragrance in general. One user said fragrance had actually “replaced emotional eating” for them.
I decided to make my investigation more official. Allure reached out to the manufacturers of popular GLP-1 drugs: Lilly (the makers of Zepbound and Mounjaro) and Novo Nordisk (the company behind Ozempic) to ask if they could comment as to if a change in one’s sense of smell is a known side effect of such medications. A representative for Lilly replied emphasizing the company’s commitment to safety, and encouraged patients to report side effects to their healthcare provider. Novo Nordisk said it “remains confident in the benefit-risk profile of our GLP-1 medicines when used consistent with their indications and product labeling.” But neither directly addressed a link between GLP-1 drugs and an altered sense of smell.
Still, I needed to know—could my GLP-1 medication have changed my olfactory processes?
The answer, according to some experts, is… maybe. And there are a few potential reasons why.
Theory 1: Bad feedback
First, I called up Igor Sapozhnikov, MD, a board-certified family medicine physician and obesity medicine specialist in Los Angeles, to see if he’d heard anything similar from his patients. He said no, not firsthand, though he has heard of similar situations from others. “This is very rare, but there is a phenomenon with these medications that can change how you appreciate smells and tastes,” he told me. Dr. Sapozhnikov believes I could be experiencing dissonance between the “feel-good neurotransmitters” of the brain—like dopamine and oxytocin—and my olfactory receptors, or what I’m smelling. “Basically, whenever you do something that makes you feel good or eat something that makes you feel good, [you activate those neurotransmitters],” he says. But because I’m taking a GLP-1 medication, these signals may—emphasis on may—be disrupted. Instead of getting the happy vibes from a vanilla scent, I’m getting a big, giant “NO.”
Theory 2: Scent memory disruption
When you smell something you like—whether it’s perfume, a bouquet of flowers, or even fresh gasoline—something happens on a molecular level. The same goes for when you smell something you hate. And we’re basically always smelling something. Hiroaki Matsunami, PhD, professor of molecular genetics and microbiology, neurobiology, and cell biology at the Duke University School of Medicine, explains that there are “tens of thousands” of different scent elements—some good, some bad, some open to interpretation—floating around us at all times. When you smell something—be it a rose or a rose perfume—its scent molecules can bind to and activate sensors (proteins called odorant receptors) in the nose.
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,” Dr. Matsunami explains. Previously, vanilla fragrances reminded me of those sweet, romantic first dates with my now-husband, which was a good memory. When I smell them now, they just remind me of feeling sick. The memory-scent association in my brain may have changed—a little bit of an olfactive "chicken or the egg" situation if you will—but no matter how fond those memories are, they're no match for the nausea.
Theory 3: Scent aversion
Because nausea was the main side effect I experienced during my first few months on the GLP-1 medication, I contacted a researcher studying nausea and the brain in GLP-1 patients: Amber Alhadeff, PhD, an associate member of Monell Chemical Senses Center in Pennsylvania and adjunct assistant professor at the department of neuroscience at the University of Pennsylvania.
She and her fellow researchers wanted to understand what was happening in the brain that made GLP-1 drugs so effective at suppressing the appetite, as well as the link between appetite suppression and nausea. What they found through their research is that “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. (This region at the base of the brain also regulates things like breathing and heart rate.)
“The most interesting thing that we found,” says Dr. Alhadeff, is that in GLP-1 medication patients, there are "two separate [neuron] populations" within that region of the brain. “One suppresses appetite without causing aversion [like nausea], and the other mediates most of the aversion effect.” But Dr. Alhadeff estimates that about two-thirds of patients deal with nausea as a side effect, and a 2025 study found that GLP-1 drugs’ side effects such as nausea are “greater in those with better taste and smell.” (Is this confirmation that I’m a super-smeller and super-taster?)
My nausea in the initial months of GLP-1 medication usage means it could be part or all of the reason I have such a visceral reaction to specific scents. Dr. Sapozhnikov compares it to the after-effects of food poisoning, like how you avoid what you were eating right before you got sick. “Whenever you get bad food poisoning or eat something where you get indigestion, that signal goes to your brain through the vagus nerve,” he says. The vagus nerve (a part of the nervous system) carries signals and messages from the brain to the rest of the body; GLP-1 medications can stimulate it. “So not only can you mess with the reward center in the brain, because this medication can do that, you’re also [potentially] stimulating the response of, ‘Don’t come at me with any food.’” Or, in my case, perfume. When I smell the fragrances I was wearing or testing at that time, I instantly remember the nausea and queasiness and put the bottles down; that might be my brain sending an “SOS!” warning not to spritz.
This association could also be why many GLP-1 drug users have noticed a lack of desire to drink alcohol, adds Dr. Sapozhnikov—something I’ve definitely taken note of on my journey thus far. (l always preferred red wine to white, but since going on a GLP-1 medication, I’ve done a complete 180. Plus, if I drink more than one glass, I get a headache that makes it feel like I drank 15.) He adds that smokers have also noted a decreased interest in smoking, potentially because of that vagus nerve stimulation.
Theory 4: Increased sensitivity to smell
In some scenarios, GLP-1 medications have been linked to an increased sensitivity to smell, says Elizabeth Hamel, a postdoctoral fellow at Monell Center with a PhD in taste and adjusted behaviors research, who has studied GLP-1 drugs. They’ve also been used to help treat loss of smell (called anosmia) in patients with Parkinson's, Alzheimer's, and dementia. “In your case, I think what might be happening is that now you have this increased sensitivity, so it might be that you’re getting a more intense perception of these smells—and things aren’t always as pleasurable at a higher intensity,” Dr. Hamel tells me. Thus, I could be experiencing my favorite scents in a new way—like the sticky creaminess of vanilla or an intense blast of rubbing alcohol notes in musk—and it’s not necessarily a fun experience.
Theory 5: Hormonal changes
Your scent preferences and palate can evolve over time or with big life changes. Dr. Matsunami uses beer as an example—it’s something that usually tastes repulsive to children who try a sip of their parents’ drink, but as they move past adolescence into adulthood, they may grow to enjoy it. This could potentially be informed by the “massive” change in hormones from childhood to adulthood, he explains, which could shift how the brain processes the smell and taste of beer.
In my case, I lost my taste for fried chicken when I was pregnant, and I had some pretty intense issues with basil and thyme—back then, pregnancy hormones could have been behind my taste and smell versions. (My taste for basil came back, but thyme? Absolutely not. Keep it out of my food, please.) But though the circumstances are very different between taking a GLP-1 medication and growing a child, this could actually be a similar situation, at least olfactorily speaking. “Why your sense of taste and smell changes when you’re pregnant is understudied,” says Dr. Matsunami, adding that in general, scientists think it has something to do with hormonal changes affecting the way a person senses food and smells. “GLP-1 is another hormone, so therefore, there may be some similarities between pregnancy and this drug treatment.” But again, as Dr. Matsunami says, there are no studies proving this or comparing the two.
The Inconclusive Conclusion
Could some of my fragrance experience be in my head? Definitely. It’s entirely possible that my brain could be associating those fragrances with the initial nausea of adjusting to the medication. As Dr. Hamel says: “Smell is one of the strongest forms of memory we have.” Or maybe, like Dr. Hamel suggested, I’m essentially super-smelling my perfumes, and it’s not as fun as it sounds. When I go off the GLP-1 medication, perhaps things will change and I’ll be ready to pull out all the gourmands again… It’s kind of a big TBD at the moment. “There's been no clinical trials yet on the role of these drugs in olfaction,” Dr. Alhadeff tells me, and Dr. Hamel says she’s hopeful there will be more research in the future. But if any scientists want to kickstart a study, you know where to find me.
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