Many people recognize it instantly: a musty, cardboard-like scent that seems to cling to older adults. Known commonly (and not so kindly) as “old people smell,” this odor isn’t caused by bad hygiene or neglect. It’s a real biological phenomenon that happens as our bodies change with age.
Where the Smell Comes From
Scientists have pinpointed a compound called 2-nonenal as the main culprit. According to Dr. Dan Wesson, a professor at the University of Florida College of Medicine, 2-nonenal forms when omega-7 fatty acids in our skin’s natural oils, or sebum, break down through a process called lipid oxidation. As we age, our bodies produce fewer antioxidants that normally prevent this oxidation, while our skin also turns over cells much more slowly. This combination allows 2-nonenal to build up and linger.
Leslie Kenny, a longevity expert and founder of Oxford Healthspan, described it as “sebum that has rusted.” Even frequent showers, scrubbing, and expensive soaps can’t wash it away because the compound binds tightly to the skin’s surface. Perfume or deodorant simply mix with the odor, creating a more stubborn, musty layer.
Research on this topic began in earnest in Japan around 2010, when studies first confirmed that 2-nonenal is unique to people over 40. Since then, scientists worldwide have investigated how lipid oxidation drives not only the smell but other signs of skin aging. In the U.S., universities like the University of Florida and institutions such as the University of Texas MD Anderson Cancer Center are exploring how antioxidants and nutrition can help slow the process.
Why It Gets Worse With Age
Several factors make this smell more common over time:
- Hormonal Changes: Declining estrogen and other hormones reduce skin cell turnover and antioxidant protection.
- Medications: Drugs for high cholesterol, depression, and ADHD can alter sweat production and metabolism.
- Chronic Conditions: Inflammation and metabolic disorders speed up lipid oxidation.
Dr. Wesson emphasized that while a gradual shift in scent is normal, any sudden change in body odor could indicate an underlying health problem and should be checked by a doctor.
The Power of Mushrooms
Unlike soap and perfume, fighting the smell effectively requires addressing it from within. That’s where diet comes in. Leslie Kenny and other researchers recommend mushrooms as one of the most promising tools to reduce age-related odor.
Mushrooms are rich in ergothioneine, a rare amino acid and antioxidant that helps block the oxidation of skin fats. They also contain spermidine, a compound that activates autophagy—the process where the body clears out damaged cells and replaces them with new ones. Both ergothioneine and spermidine slow down the production of 2-nonenal and improve skin renewal.
In a clinical study published in the Journal of Traditional and Complementary Medicine, adults aged 50 to 79 who took daily champignon mushroom extract showed clear improvements in body odor, bad breath, and even pillow smells. The higher the dose, the better the results.
How to Use Food to Smell Fresher
Kenny suggests eating mushrooms three to four times per week. Shiitake, oyster, and champignon varieties have the highest levels of ergothioneine and spermidine. You can include them in stir-fries, soups, omelets, or even as supplements if you prefer capsules.
While no food will erase the odor overnight, a consistent diet rich in antioxidants may gradually reduce it. Studies also link mushrooms to a lower risk of cognitive decline, stronger bones, improved insulin sensitivity, and better immune function.
Other helpful habits include:
- Eating more colorful vegetables and fruits for additional antioxidants
- Drinking enough water to keep skin hydrated
- Using skincare with antioxidants like vitamin C and E
“Old people smell” is real and common, but it isn’t inevitable or untreatable. By understanding the biological processes behind it and making changes to diet and lifestyle, you can reduce the buildup of 2-nonenal and keep your skin healthier longer.
Instead of simply trying to mask the scent, targeting it from within—with the help of nutrient-dense foods like mushrooms—offers a science-backed, practical approach to aging more gracefully.
