Why Do Old People Smell? The Science of Body Odor and Aging

Full length side view of female nurse pushing senior man on wheelchair at hospital corridor
There are several reasons why the retirement home smells different from the high school gym. Maskot / Getty Images

"Old people smell" is a real phenomenon. The chemical composition of odor-producing molecules changes as we age, plus there are other factors that affect scent. Here's a look at the causes of "old people smell," the biological reason for changing odor, and tips for minimizing the scent (should you wish to).

Body Odor Changes as We Age

There are several reasons why the retirement home smells different from the high school gym:

  1. Body chemistry changes over time. The characteristic scent associated with the elderly is the same, regardless of a person's ethnicity or culture. Scientists have figured out what's happening. As people age, fatty acid production in the skin increases while antioxidant production decreases. Polyunsaturated fatty acids are oxidized, sometimes increasing the amount of a chemical called 2-nonenal. Nonenal is an unsaturated aldehyde known for its grassy, greasy scent. Some researchers did not detect 2-nonenal, but did find higher levels of the stinky organics nonanal, dimethylsulfone, and benzothiazole in the body odor of older subjects.
  2. Illness and medication change a person's odor. Older people are more likely to take a prescription than younger people. Both the underlying medical condition and the drug can affect body odor. For example, taking garlic as a supplement is known to affect odor. Body odor is a side effect of bupropion hydrochloride (Wellbutrin); leuprolide acetate (Lupron), used to limit hormone production; topiramate (Topamax), used to treat epilepsy and seizures; and omega-3-acid ethyl ester (Lovaza), used to reduce blood fat levels. Several drugs increase perspiration rate, including nonsteroidal anti-inflammatory drugs (NSAIDS), antidepressants, and codeine sulfate. Medical conditions that affect body odor include diabetes, hyperthyroidism, liver disease, kidney disease, menopause, and schizophrenia.
  1. Older people may bathe and change clothes less often. An elderly person may need help bathing, fear falling on a slick bathroom floor, or experience pain getting into and out of a tub.
  2. The sense of smell, like other senses, declines with age. So, an older person may not self-identify an unpleasant smell or may apply an obnoxious amount of cologne or perfume.
  1. Dental hygiene significantly affects a person's odor. As we age, the mouth produces less saliva, reducing the best natural defense against bad breath. Periodontal (gum) disease is more common in older people, also contributing to halitosis (bad breath). Dentures and bridges can retain bacteria and fungi, leading to infections and a musty smell.
  2. Aging affects our ability to sense dehydration. As the pituitary gland sends weaker signals for thirst, older people tend to drink less water. Dehydration leads to stronger-smelling perspiration and urine and can cause skin to develop an odor from increased shedding of dry cells.
  3. Older people tend to have older belongings, which means their possessions have had time to develop odors. If you're surrounded by old-smelling objects, you carry some of their scent.

Why Body Chemistry Changes

There may be an evolutionary reason that odor to change as a person ages. According to Johan Lundström, a sensory neuroscientist at the Monell Chemical Senses Center, humans use scent to find mates, identify kin, and avoid sick people. Lundström and his team conducted a study which found people were able to identify the age of a person based solely on body odor. The experiment also found odors associated with old-age (ages 75 to 95) were deemed less unpleasant than those from middle-age and young perspiration donors.

The odor of old men was deemed "best." The odor of older women ("old lady smell") was judged to be less pleasant than that of younger women.

A logical conclusion of this study would be that the scent of old men acts as sort of nonverbal advertising for a mate proven to have genes with high survival potential. The scent of an older woman might mark her as past childbearing age. However, test subjects reacted neutrally to body odor from all age groups, so natural biochemical changes do not, of themselves, produce an unpleasant aroma.

Getting Rid of Old Person Smell

Keep in mind, the natural body odor of an older person is not considered objectionable! If an elderly person stinks, it's probably due to one of the other contributing factors.

Increased attention to personal hygiene and upping water intake should be enough to address unpleasant odor in a healthy individual.

However, if a person's smell is truly rank, there's probably an underlying medical cause. A trip to the doctor and dentist may be in order, along with a review of medications that may affect body odor.

There are actually products marketed specifically to address "old people smell." In Japan, the odor even has its own name: Kareishu. The cosmetic firm Shiseido Group has a perfume line intended to neutralize nonenal. Mirai Clinical offers soap and body wash containing persimmon extract, which contains tannins that naturally deodorize nonenal. Another way to combat nonenal and other smelly aldehydes is to stop fatty acid oxidation by using a lotion that moisturizes the skin and replenishes antioxidants.

Key Points

  • Body odor naturally changes as people age, plus there are other factors that contribute to "old people smell."
  • Research indicates people generally don't perceive an elderly person's natural body odor to be unpleasant.
  • Other factors can contribute to unpleasant body odor, including medication use, underlying illness, diet, and perfume use.
  • Body odor can be minimized by increasing bathing frequency and using a deodorizing antiperspirant.

References

  • Gallagher, M.; Wysocki, C.J.; Leyden, J.J.; Spielman, A.I.; Sun, X.; Preti, G. (October 2008). "Analyses of volatile organic compounds from human skin". British Journal of Dermatology. 159 (4): 780–791.
  • Haze, S.; Gozu, Y.; Nakamura, S.; Kohno, Y.; Sawano, K.; Ohta, H.; Yamazaki, K. (2001). "2-Nonenal Newly Found in Human Body Odor Tends to Increase with Aging". Journal of Investigative Dermatology. 116 (4): 520–4.