Spoiler: Deodorant won’t fix it.
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Published on September 29, 2026
In This Article
- What Is the “Aging Scent” Molecule?
- When Does It Start?
- Why Does It Happen?
- What Can You Do About It?
Baking Soda and Vinegar Isn’t a Cleaning Hack Close
My brother recently texted me, “Mom and Dad’s house smells old.” To be clear, my parents are very clean—and they burn plenty of yummy candles—but lately, something has smelled a little…stale. If you’ve noticed a similar scent around older loved ones, it may not be mothballs or musty clothes. Before anyone comes for me—or my parents—this isn’t an insult or a hygiene issue. It’s a natural biological change that can happen to all of us if we’re lucky enough to age. There’s an actual scientific explanation for it—and, gulp, the change can begin in your 40s. Dermatologist Shereene Idriss, MD, explains what causes so-called “old person smell,” why one commonly missed spot can make it worse, and what actually helps. The more you know, right?
- Shereene Idriss, MD, board-certified dermatologist and founder of Idriss Dermatology and Dr. Idriss skincare in New York City
What Is the “Aging Scent” Molecule?
The molecule that contributes to this distinctive scent is called 2-nonenal. Scientists first identified it in human body odor in 2001, detecting it only in study participants ages 40 and older.
Unlike typical body odor, 2-nonenal isn’t caused by sweat. Idriss compares the scent to slept-in bedsheets, where dead skin cells, sweat, and skin oils collect and react with oxygen over time.
“It doesn’t even smell like sweat—it smells like old bedsheets,” Idriss explains in a recent Instagram video. The resulting scent is often described as waxy, grassy, stale, or slightly oily (woof).
When Does It Start?
The process can begin as early as your 40s. That doesn’t mean you’ll wake up on your 40th birthday smelling entirely different. However, levels of 2-nonenal appear to increase gradually with age, and how noticeable the scent becomes can vary from person to person.
“As we get older, the fats sitting on the surface of our skin become more prone to oxidation,” Idriss says. “When they break down, they create 2-nonenal.”
Why Does It Happen?
Our skin is naturally coated with lipids, or fats, that help keep it moisturized and protected. As we age, the composition of those fats changes, making them more vulnerable to oxidation. As the skin’s oils oxidize and break down, they release 2-nonenal.
It’s a normal biological change—not a reflection of someone’s cleanliness. But according to Idriss, one often-missed area can intensify the odor: behind the ears.
“It’s a perfect odor trap,” she says. “It is warm, it is oily, and it is tucked away.” This allows sebum, dead skin cells, and bacteria to accumulate, especially if you routinely forget to wash there.
What Can You Do About It?
First, make a point of washing behind your ears every time you shower. Idriss specifically recommends using persimmon soap. Persimmon extract contains plant compounds called tannins that are thought to help neutralize odor molecules such as 2-nonenal rather than simply covering up the scent. However, published research showing that persimmon soap works better than ordinary soap is still limited—so the most important step is thoroughly and consistently cleansing the area (Idriss says both body wash and shampoo will do the trick).
After washing and rinsing, you can gently swipe a cotton swab along the folds and skin behind your ears to remove lingering buildup. (Avoid inserting it into the ear canal.)
Idriss also recommends regularly laundering anything that touches your skin, including washcloths, towels, pillowcases, and bedsheets. To be honest, writing this article has given me newfound motivation to wash my sheets even more often. Skin oils and odor compounds can transfer to fabric and linger—which may help explain why the scent sometimes seems to permeate a room or home.
Finally, don’t assume applying more deodorant will solve the problem. “This is not a sweat problem,” Idriss explains. “It is a fat-oxidation problem.” Deodorant may temporarily mask the scent, but it doesn’t address the oxidized skin oils contributing to it.
As Idriss puts it, “Apparently, anti-aging is not just about how you look, but also about how you smell.”
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