I turned 38 two weeks ago. It’s something I feel uncomfortable enough admitting to myself, let alone to the internet, but here we are. Like the helium balloon I kept from my surprise party, which has started to sag and wrinkle in the time since, the realization that I’m approaching the big 4-0 has been, well… a little deflating. Not because there’s anything wrong with getting older. It’s a privilege to age, and I have enormous respect for the people who’ve been doing it longer than I have. But it’s a little daunting when every reel your algorithm shows you treats aging like a problem to be solved: fighting wrinkles, gray hairs, and so on. I’d largely accepted those things, but the fact that aging can also change the way we smell? That wasn’t exactly on my bingo card. Thinking about it, though, it makes sense. I still remember precisely how my late grandmother smelled. Not in a bad way—it’s simply one of those sensory details that remains tied to a person long after they’re gone. And I’ve recognized that familiar scent in the homes of other older friends and relatives, too. But it turns out it’s not just perfume, lotion, and mothballs. Experts say we really do smell different with age, and “It’s one of the most universal, least talked-about parts of being human,” according to dermatologist Dr. Roya Javid. This is exactly the kind of thing that sends me down a research rabbit hole: wrinkles had me learning about peptides and serums; “preserving muscle mass” had me oversubscribing to strength training programs. This time, I had to find out what the experts have to say about “old person smell”—and whether it’s actually something we should be worried about. Raymond Petrik / Pexels (not the actual photo) “Old person smell” certainly sounds a little harsh—unflattering at best, mocking at worst. But it seems there really is a distinctive scent associated with getting older. And apparently, it’s not limited to any particular group: “Older folks give off a characteristic scent that’s independent of race, creed, or diet,” according to Elizabeth Norton, writing for Science, noting that the Japanese even have a name for it: kareishu. And while it might’ve been news to me, researchers have been onto this for a while. A 2012 study published in PLOS ONE, titled “The Smell of Age: Perception and Discrimination of Body Odors of Different Ages,” set out to determine whether people could actually identify age from body odor. The study was co-authored by sensory neuroscientist Johan Lundström, who first became familiar with “old person smell” while visiting his mother at the nursing home where she worked in Sweden. Years later, he encountered the same distinctive smell while giving a talk at another nursing home, prompting him to wonder whether humans could actually detect age this way. To find out, Lundström and his colleagues collected body-odor samples from donors aged 20 to 30, 45 to 55, and 75 to 95. For five nights, the donors slept in T-shirts with absorbent pads sewn into the armpits, washing with odorless soap and shampoo and avoiding alcohol, smoking, and spicy food. The samples from each age group were then combined for participants to sniff and assess. So, could people actually tell how old someone was from the samples? The results suggested they could: the participants were able to distinguish the body odor of elderly people from that of younger and middle-aged people. karlyukav / Magnific (not the actual photo) One of the main compounds associated with this shift in body odor has a name that sounds far more complicated than it is: 2-nonenal. Dr. Sonal Choudhary, a dermatologist from the University of Pittsburgh School of Medicine, describes it as “a naturally occurring, odor-producing molecule that forms when certain fats on the skin surface undergo oxidation.” There’s evidence for this connection going back decades. In a 2001 study published in the Journal of Investigative Dermatology, researchers detected 2-nonenal significantly more frequently in the body odor samples of participants aged 40 and older, describing it as having “an unpleasant greasy and grassy odor.” What made the 40-and-overs so special? Apparently, it has to do with the changes that happen to our skin as we age. As dermatologist Dr. Roya Javid explains, “Our skin is coated in a thin layer of natural oils called skin lipids. They keep skin soft, waterproof and protected.” Those lipids contain fatty acids, and their composition changes as we age. Meanwhile, the skin’s ability to protect itself from everyday wear and tear declines. Together, these changes can make the skin’s oils more susceptible to oxidation, creating more opportunity for 2-nonenal to form. In short, as Javid puts it: “It’s just oil quietly changing over time, the same way metal changes when it’s exposed to air.” SHVETS production / Pexels (not the actual photo) But 2-nonenal isn’t the only factor that can influence how someone smells as they age. Choudhary explains that the compound gets most of the attention simply because it was one of the first age-related odor markers identified—but body odor actually comes from a mix of skin oils, sweat, the skin’s microbiome, oxidative processes, medications, diet, health conditions, and environmental factors. As she puts it, “Reducing the conversation to one chemical misses much of the underlying biology.” Javid makes a similar point, noting that “We don’t yet know why some develop a stronger scent than others,” adding that an individual’s skin-oil composition, genetics, skin microbiome, hygiene practices, clothing, health, and environment may all play a role in how much 2-nonenal is produced and how long it remains on the skin. In other words, “old person smell” could be seen as less a single chemical signature than a combination of biology and everyday context. cottonbro studio / Pexels (not the actual photo) Does all this mean that once you’ve blown out the birthday candles—all 40 of them—you’ll wake up the next day smelling noticeably different? Not quite. Although the 2001 study found 2-nonenal in the body odor of participants aged 40 and older, as with most things in aging, that doesn’t mean anything suddenly changes when you reach that milestone. “It’s more of a gradual biological drift,” as Dr. Pablo Prichard puts it. There’s plenty of variation in how that process plays out, too. Choudhary notes that “2-nonenal begins increasing around middle age and may plateau or vary considerably between individuals rather than steadily rising throughout life.” So there’s no magic age at which someone suddenly develops an “old person smell,” and when—or even how noticeably—it appears can vary from one person to another. Perhaps more importantly, though, there’s no reason to view these changes as something to dread or feel ashamed about. As Javid explains, “It’s just biology, unfolding on schedule, the same way we grow taller, then our hair goes gray. Every single person on the planet goes through these same transitions.” gpointstudio / Magnific (not the actual photo) In any case, research suggests that “old person smell” may not be as unpleasant as the stereotype might have us believe. In Lundström and his colleagues’ study, the participants proved that older folks do give off a distinguishable odor. Yet their samples weren’t necessarily judged to be the most unpleasant. As Ferris Jabr summed up, “Middle-aged man musk took top prize for intensity and unpleasantness,” while volunteers rated the odors of middle-aged women as the most pleasant and “whiffs of old man” as the least intense. Lundström has also suggested that context can influence how we perceive a smell. He noted that it’s easy to associate advanced age with smells linked to illness or hygiene if “you only experience it if you go to a retirement home, or some old guy’s home.” But those associations don’t necessarily tell us anything about the odor of an older person’s body itself. And there’s another reason not to assume that a distinctive smell is automatically an unpleasant one. Jabr pointed back to the earlier research on 2-nonenal, noting that “the compound has also been linked to the scent of cucumbers and aged beer, which are not distasteful to most people.” He also noted that “others have compared old people smell to old book smell, which most people find benign at worst and enjoyable at best.” So really, perhaps the more accurate conclusion is simply that aging can give the body a characteristic scent—and whether we interpret that scent as pleasant, unpleasant, familiar, or even comforting may have as much to do with context and association as with the chemistry itself. Gustavo Fring / Pexels (not the actual photo) It turns out you can’t stop 2-nonenal from forming entirely, but you may be able to minimize the processes that contribute to it. Experts point to the same handful of basics that tend to come up with most aging concerns: eating well, exercising, getting enough sleep, managing stress, and cutting back on alcohol. The idea is that these habits can help reduce oxidative stress, which plays a role in the formation of 2-nonenal and may be one reason two people of the same chronological age can smell quite different from one another. As for actually washing it away—don’t get your hopes up. 2-nonenal is oily and can cling to skin and fabric rather than rinsing away like sweat. And because your body keeps producing it, soap can only remove some of it. “It’s hard to get rid of this molecule, because it’s very sticky,” says Danielle Reed of the Monell Chemical Senses Center. Deodorant may cover the smell temporarily, but it won’t remove 2-nonenal. And while there are products marketed specifically to neutralize it—including persimmon-based soaps, which contain tannins that may help bind to 2-nonenal and wash it away—experts say the evidence for these products is still limited, so they’re better thought of as promising than proven. However, no matter how noticeable the smell is, it’s not an embarrassing “problem” that needs to be scrubbed away. As Javid puts it, it’s “just a natural byproduct of skin aging—not dirt, not poor hygiene.” Of course, a sudden change in body odor is worth getting checked out, but if you’re simply getting older, there’s no reason to be ashamed of smelling a little different. After all, as Javid points out, “the science says you’re worrying about something that, objectively, isn’t as bad as the stereotype.” And honestly, aging comes with enough to worry about already. Thankfully, this isn’t one more thing to panic over—or feel like you need to throw a fancy serum at.
