Ask Dr. Pete: What Is “Old-Person Smell”? The Science Behind Aging Body Odor

Ask Dr. Pete: What Is “Old-Person Smell”? The Science Behind Aging Body Odor

We get a lot of laundry questions — including this one:

“What is ‘old-person smell,’ and why is it so hard to get rid of?”

You’re not alone in asking. Customers have written in looking for real answers, so we’re breaking it down — without judgment, and with science.

close up of senior man's hands

What causes “old-person smell”?

“Old-person smell” is a casual term for nonenal, specifically 2-nonenal — a compound that naturally forms as skin chemistry changes with age.

As we get older, the skin produces more unsaturated fatty acids, while natural antioxidant defenses decline. When these fatty acids react with oxygen, they oxidize and break down into 2-nonenal.

The result is a distinct odor often described as musty, grassy, or slightly greasy — sometimes compared to old cardboard or aged beer. This process is normal, unavoidable, and not related to poor hygiene.

Why aging body odor is hard to wash away.

Unlike most body odors, 2-nonenal is not water-soluble. It’s oil-based and waxy, which means water alone can’t remove it effectively.

Even regular showering may not fully eliminate the scent if soaps aren’t designed to break down oils. Nonenal also tends to bind to fabrics like clothing, sheets, and towels, where it can linger after washing — especially if detergents aren’t strong enough.

This is why aging body odor can feel “stubborn,” even with good hygiene habits.

basket of laundry next to a washing machine on green tile floor

How to reduce nonenal odor (on skin and fabrics).

There’s no single fix, but a combination of skin care, fabric care, and lifestyle habits can help reduce nonenal buildup.

Skin care

In Japan, persimmon-based soaps and lotions have long been used to combat nonenal. These products contain tannins, which may help neutralize the compound, though research is still ongoing.

Daily showers using warm water and soaps with strong oil-removal properties — ideally with antioxidant or antibacterial ingredients — are also important.

Fabric care

Because nonenal binds to fabrics, frequent washing is key. Look for enzymatic laundry detergents with strong grease and body-oil-removal power, plus oxygen bleach (like Dirty Labs Bio Enzyme Laundry Booster) to fully break down odor-causing compounds.

Lifestyle support

Antioxidant-rich foods — such as mushrooms, berries, and other plant-based foods — may help reduce oxidative byproducts in the body over time.

The Takeaway

What people call “old-person smell” isn’t a flaw or a hygiene issue. It’s a normal biochemical change that happens with aging skin.

Understanding what causes nonenal helps remove the stigma — and makes it easier to care for both your body and your laundry in a way that’s effective and grounded in science. Aging has a scent, just like youth does. The goal isn’t to erase it, but to support the body and the fabrics around it with the right tools.