Why Do We Smell Different As We Age?

The scent of old books can conjure happy memories of discovering stories in a school library, or rummaging through a used-book store full of buried treasures. A vintage perfume can remind us of the glamorous great-aunt who wore it. But that musty “old person smell”? That’s a different situation.

The particular scent associated with older people — or “human aging-related body odor,” as the scientists call it — is a biological fact of life. Here’s what causes it, plus a few simple ways to make it less noticeable.

Eau de Old

Humans aren’t the only animals whose natural body odor changes with age. Otters, rabbits, mice, and even owls experience this phenomenon and can tell the ages of members of their species by smell. Our noses can sense it, too: A 2012 study showed humans in a blind smell test had the ability to identify older people by how their particular scent differed from those of younger and middle-aged people.

Chemically, the apparent primary source of the smell is 2-nonenal, a compound “with an unpleasant greasy and grassy odor,” according to the 2001 study that first characterized it. Participants in the smell test of that study detected 2-nonenal only in people who were 40 and older. The compound is released when certain fatty acids on the skin surface start to oxidate (or break down) naturally with age.

Researchers don’t know why some people produce more 2-nonenal than others. The intensity of an individual’s “old person smell” is likely influenced by genetics, the skin’s microbiome, their general health, and the medications they take. The production of 2-nonenal doesn’t always increase at the same rate with age; it might plateau at some point, or not.

Smell is also a subjective experience, and what some consider to be “old person smell” may actually be a combination of scents culturally associated with older people — think menthol (a minty compound in pain-relieving creams) or classic perfumes with powdery, flowery notes. Or, an individual might perceive “old person smell” as a particular scent associated with a specific person, like a grandfather’s aftershave.

It’s Not Poor Hygiene

To be clear, “old person smell” isn’t about needing to take a bath. It’s a byproduct of the skin’s natural aging process, and it happens to all of us. But if you’re concerned about your scent, there are some easy ways to make it less apparent.

Showering or bathing regularly with a lightly scented soap and moisturizing afterward will keep the skin barrier healthy, and using an antiperspirant-deodorant combo will combat sweat as well as odors. Though there’s not much scientific evidence showing that a healthy diet reduces unwanted body odor, it can’t hurt. A diet heavy in fruit, vegetables, and other plant-based foods benefits your overall health, and could, in theory, reduce the need for medications that can alter your body’s smell.

Another possible fix? Limiting behaviors that cause excessive oxidative stress, the main driver of 2-nonenal production. In addition to eating plenty of antioxidant-rich fruits and vegetables, not smoking and protecting your skin from sun exposure “are sensible antioxidation habits,” Dr. Arshad Rather, a geriatrician at University College London Hospitals, told The Guardian. 

Laundering sheets, towels, and clothes on a regular basis may also reduce the presence of “old person smell,” since oils from your skin can linger in fabrics and give them a stale and musty odor over time. You may not be able to eliminate every unwanted whiff, but these simple habits should help.

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