Your body odor can change throughout your life. Think of a newborn baby — they have that distinct, fresh scent. Now, think of a teenage boy. They, too, have a distinct scent that’s very different from a baby’s.

Older adults are no different. Many describe their scent as being mildly sweet and musty. And despite what popular culture might try to say, a suggests most people usually don’t mind this smell at all.

The study’s authors believe people tend to find the scent more unpleasant when they know it’s coming from an older person. This suggests there’s likely some age discrimination at play in how people perceive body odor.

But what causes our body odor to change with age, and why does it happen?

Contrary to harmful stereotypes of older people, age-related changes in body odor likely have nothing to do with personal hygiene. Instead, experts think it’s the result of odor compounds and bacteria interacting on the skin. The major odor compound at play is called 2-nonenal.

When certain chemicals break down in the body with age, 2-nonenal is one of the byproducts. The breakdown of omega-7 unsaturated fatty acids may be the biggest source of 2-nonenal.

Experts have only detected 2-nonenal in people over the age of 40. Levels appear to only increase with age. While environmental and lifestyle factors can also influence body odor, 2-noneal appears to be responsible for the distinct, slightly musty odor associated with older people.

Keep in mind that experts are still trying to fully understand how body odor changes with age. While 2-noneal seems like a probable cause, there’s still a chance it doesn’t play much of a role.

Instead, it may just be the result of interactions between skin gland secretions and bacteria living on your skin. The type of bacteria that live on your skin are different in various life stages. Likewise, the chemicals and compounds in your body can change with time, too.

While 2-nonenal is likely responsible for how body odor changes with age, it’s still unclear why this change happens. But experts believe evolution is part of the picture.

Remember, it isn’t just older adults who have a distinct smell. Infants, teenagers, young adults, and middle-aged adults each tend to have slightly different body odors. Experts believe these specific scents help keep the human species alive and well.

For example, that fresh baby smell may be more appealing to mothers, which helps with bonding. In adults, body odor may help signal someone’s fertility or health to find an optimal mate.

Since the discovery of 2-noneal, several companies have started developing personal care products designed to mask the scent of older people, particularly in Japan. But there’s no evidence that these products do anything to target 2-nonenal.

Plus, there’s evidence that people generally don’t mind the smell associated with older people. In fact, that 2012 study found that participants rated the odors of older individuals as less unpleasant and less intense than the odors of some younger groups.

For the study, 44 men and women were divided into three different age categories: 20 to 30, 45 to 55, and 75 to 90. They were asked to sleep in a shirt specially fitted with underarm pads that could absorb odor for five consecutive days.

Participants were also asked to avoid foods that could interfere with their urine’s natural smell while on the sleep test. These included foods containing a lot of spices.

At the end of the five days, the underarm pads were collected and cut into quarters. Each piece was placed in a glass jar. The study’s authors asked individuals to smell the jar and guess the person’s age and sex.

The testers had a hard time detecting differences in scent between young and middle-aged people — they smelled too similar. They had a much easier time identifying samples from the study’s oldest group.

These results suggest that older people do have a very distinct smell, but it’s not necessarily unpleasant or intense.

If you’re concerned about age-related changes in your body odor, you don’t need to purchase any products specially formulated to target 2-noneal. Any scented product you enjoy will help mask the smell.

Alternatively, consider wearing your new scent as a badge of honor. Chances are, most people won’t even notice. And if they do, they likely won’t have any problem with it.

Body odor naturally changes as you age. For older people, this change in smell is likely due to an increase in levels of a compound called 2-nonenal.

No matter the cause, there’s no reason to run from these changes. Research suggests that, while people recognize older adults as smelling different, they don’t necessarily consider it an unpleasant smell.