There is a smell many people recognize before they ever find the words for it. It might appear when you open a relative’s old closet, step into a grandparent’s home after months away, or unfold a blanket that has been part of the family for years.
People often call it “old person smell,” a phrase that can carry affection, discomfort, or both.
Scientists have looked into that familiar scent, and the reality is more complicated than the stereotype suggests. Researchers have identified a compound linked to aging, studied how it develops, and tested how younger adults actually perceive the odor.
The result challenges a common assumption: while age-related scent changes are biologically real, the idea that older people naturally smell unpleasant or that the odor reflects poor hygiene does not match what studies have found.
The Molecule Behind the Myth
Researchers didn’t simply confirm that body odor changes with age; they found the specific compound most likely driving it.
In 2001, scientists studying human body odor identified a compound called 2-nonenal in participants who were 40 and older. The compound was not detected in the younger adults involved in the research. A type of aldehyde, 2-nonenal forms when oils on the skin’s surface undergo oxidation, a process influenced by changes in the skin as people age.
“As we age, several things happen simultaneously in our skin,” said Dr. Sonal Choudhary to HuffPost. “Antioxidant defenses in the skin decline, the composition of our sebum changes, and our cumulative UV exposure and environmental stress increase oxidative damage in the skin.”
Levels of 2-nonenal generally become more noticeable around middle age and can increase further later in life. But the intensity differs from person to person. Genetics, skin characteristics, and lifestyle all play a role, meaning there is no single version of an “aging smell” shared by everyone.
Why Washing Doesn’t Fix It
The reason 2-nonenal can linger after bathing comes down to chemistry, and it reframes what it means to notice a different scent on an older relative.
Unlike some odors that disappear with soap and water, 2-nonenal has properties that make it difficult to remove completely.
“It’s hard to get rid of this molecule, because it’s very sticky,” Danielle Reed, chief science officer at Monell Chemical Senses Center, explained to HuffPost. “It loves to stick to your skin and it loves to stick to fabrics. You’ll remove some of it when you bathe, but your body is constantly making it, so washing isn’t a cure.”
Because the compound is not water-soluble, traces can remain on skin and clothing even with regular washing. Experts describe this as a normal biological change, not a sign of neglecting personal care.
Related: 10 Old Age Habits That Push People Away Without Realizing It
The Study That Upended the Assumption
When researchers stopped analyzing compounds and instead had younger adults rate what they smelled, the results didn’t match the cultural assumption.
In 2012, researchers wanted to understand not just what chemicals were present in body odor, but how people actually experienced those smells. They collected underarm odor samples from three groups: adults in their 20s, adults in their mid-40s to mid-50s, and adults aged 75 to 95.
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Participants wore T-shirts with odor-absorbing pads for five nights while avoiding alcohol, fragrance, and spicy foods. 41 younger adults then rated the samples based on intensity and pleasantness.
The results surprised many people. The oldest group’s samples were rated as less intense and less unpleasant than samples from younger and middle-aged adults. Participants still identified the oldest group’s odor more consistently, suggesting an age-related scent exists. But the smell itself was not viewed the way popular culture often portrays it.
“I think it’s true that old people smell a certain way, but the idea that the smell is negative may largely be social stigma,” researcher Johan Lundström said.
What “Grandparent Smell” Is Actually Made Of
Much of what people associate with the scent of older relatives may have less to do with body chemistry than with memory, environment, and everything that surrounded the person.
A familiar smell can bring back a memory almost instantly because the brain systems involved in smell are closely connected with emotion and recall. That is why walking into an old family home can feel like stepping into the past before a person has even identified what they are smelling.
The scent people describe as “grandparent smell” is often a combination of many things. It may be a perfume or cologne someone wore for decades, a favorite laundry detergent, the bathroom soap, or the foods regularly prepared in the kitchen.
Furniture, carpets, books, and household products can also become part of that familiar scent over time. In many cases, what people associate with an older relative is not a single biological marker but a collection of smells tied to a person, a place, and years of shared memories.
What Actually Helps and Where the Evidence Gets Thin
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Practical steps exist for managing age-related odor, but the consumer market has moved well ahead of what the research supports.
Basic habits remain the most established approach: regular bathing, clean clothing and bedding, dental care, breathable fabrics, and well-ventilated living spaces. More careful laundering and skin care routines may also help reduce the buildup of odor-causing compounds.
Some products have been marketed specifically around 2-nonenal. Persimmon-based soaps, for example, have attracted attention because their tannins may theoretically interact with the compound. However, experts disagree on how strong the evidence is behind many of these claims.
Research involving eggplant-derived compounds has shown some ability to capture 2-nonenal in laboratory settings, but those findings do not prove that the approach works in everyday human use. Larger studies have not established a guaranteed solution or a permanent way to eliminate age-related scent changes.
Do you think our discomfort with “old person smell” is more cultural than chemical?
