According to dermatologists and medical researchers, human body odor naturally changes with age due to the chemical compound 2-nonenal, which is produced when skin lipids oxidize and break down. This biological transition, commonly referred to as “old person smell,” begins around age 40 and represents a universal, normal part of skin aging rather than a sign of poor hygiene.
What Causes 2-Nonenal Production in Aging Skin
Human skin is coated in a thin layer of natural oils called skin lipids, which keep skin soft, waterproof, and protected, according to Dr Roya Javid, a dermatologist in Monterey, California. These lipids consist of fatty acids that change in composition as people age. Simultaneously, the skin’s ability to fight off everyday wear-and-tear slows down, leaving oils more exposed.
When these exposed oils break down through oxidation, they release 2-nonenal. “It’s just oil quietly changing over time, the same way metal changes when it’s exposed to air,” Javid says. She notes that the process is a natural byproduct of skin aging rather than dirt or poor hygiene.
Levels of 2-nonenal vary significantly by individual. According to Javid, an individual’s skin-oil composition, genetics, skin microbiome, hygiene practices, clothing choices, health, and environment all play a role in how much 2-nonenal is produced and how much stays on the skin throughout the day.
Did you know? Every stage of life features a signature scent. Babies smell sweet and milky because their scent glands haven’t switched on yet, while puberty introduces a stronger, muskier smell driven by hormones. Later in life, changes in the skin’s natural oils give people a different scent.
When Does Body Odor Change With Age?
Research shows that age-related body odor changes can begin much earlier than many people expect. A Japanese study from 2001 tested the skin of subjects between the ages of 26 and 75 and detected 2-nonenal starting at age 40.
However, Dr Arshad Rather, a consultant geriatrician and general physician at Medical Express Clinic in London, explains that this detection does not mean people suddenly wake up with a noticeable new aroma. “Research suggests 2-nonenal increases gradually the older you get, particularly past middle age,” Rather says. “It’s not a switch flipping at 40 – more a dial slowly turning up.”
Perception Versus Reality of Older Adult Body Odor
Any negative feelings people hold toward “old person smell” stem from a perception problem rather than reality, according to Javid. A blind test conducted in a 2012 study demonstrated that the 2-nonenal scent may not be disagreeable to others.
Researchers asked 41 young adults to smell T-shirts worn by individuals from three age groups: young adults aged 20 to 30, middle-aged adults aged 45 to 55, and older adults aged 75 to 95. The study found that the odor from older adults was rated as less intense and less unpleasant than the odor from younger groups.
Dr Johan N Lundström, a professor of psychology at Karolinska Institutet in Sweden and one of the study’s authors, noted that his team was surprised by the results. The researchers initially hypothesized that body odor pleasantness would follow a linear trend, with the youngest group rated highest and the oldest group rated lowest. “The elderly have a clearly separate body odor quality, but it was not rated as being all that negative,” Lundström says.
How to Manage Age-Related Body Odor
Experts state that there is no way to completely stop 2-nonenal from developing. Regular bathing washes away surface scent, but soap and water will not fully remove the chemical because it is generated continuously beneath the skin. Deodorants can only temporarily cover up the smell.
Regularly washing clothes and bed sheets, as well as airing out rooms, helps reduce the odor in a home environment. Because 2-nonenal does not easily wash out of fabrics, the scent can linger even after dedicated cleaning practices.
Pro Tip: While some body wash products are marketed as neutralizing 2-nonenal, such as soap made with persimmon, Javid notes that while there are some anecdotal accounts that these help, scientific evidence is lacking.
Rather suspects a connection exists between 2-nonenal production and a person’s lifestyle and diet, noting that more studies are needed. “Since the smell comes from an oxidation reaction, reducing oxidative stress is a sensible target,” Rather says. Eating antioxidant-rich foods—such as colorful fruits, vegetables, and sources of vitamins C and E—can help reduce oxidative stress.
“Not smoking and protecting your skin from sun damage are sensible anti-oxidation habits too,” Rather adds.
Javid urges individuals who notice 2-nonenal production not to feel self-conscious or spend excessive money on specialized soaps. “Focus on the things that support your skin generally: antioxidants, less sun damage, less smoking, good hydration,” she advises. “And know that the science says you’re worrying about something that, objectively, isn’t as bad as the stereotype.”
Frequently Asked Questions
What causes old person smell?
Old person smell is caused by 2-nonenal, a chemical compound produced when skin lipids and fatty acids oxidize and break down as people age, according to Dr Roya Javid.
At what age does 2-nonenal start to develop?
A Japanese study from 2001 detected 2-nonenal starting at age 40, with levels increasing gradually as people grow older, according to Dr Arshad Rather.
Can old person smell be washed away with soap?
Regular bathing washes away surface scent, but soap and water will not fully remove 2-nonenal because the chemical is generated continuously by the skin, according to dermatologists.
Is the scent of 2-nonenal considered unpleasant by others?
A 2012 study published by researchers including Dr Johan N Lundström found that body odor from older adults was rated by young adults as less intense and less unpleasant than body odor from younger age groups.
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