You walk into your grandparents home and there's that odor that you only smell around them or around other senior citizens. It's often described as smelling a bit musty, stale, or like mothballs.

When we're little it's a bit more annoying and most of us as kiddos assume it's just our own grandparents Once we get older we realize not only are we not alone, but we may even start to smell it when we visit our own parents.

We may smell it when we walk past older people, sit down at a table in a restaurant where they were just dining, or even in an elevator. It's a universal smell that's not just contained inside an older person's home but tends to follow them everywhere.

So what exactly is it?

According to the Scientific American website, this unusual smell, that's not necessarily unpleasant rather it's just unique to the older generation, lingers like perfume, especially in confined places, while pre-senior citizen age there aren't any unique smells within age groups except newborn babies.

READ ON: If You Smell One of These Food-Like Scents in Home Get Help Fast

It's believed that just like everything else with our bodies changes as we age, the chemical make-up of bacteria mixed with our skin gland secretions change as we get older according to the Healthline website.

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.

Basically, the types of bacteria that live on your skin go through various stages in the aging process as do the comical compounds in our body over time. According to Scientific American, scientists call the main odor compound at play "2-nonenal."

2-nonenal only exists in us after we've turned 40 with minimum levels that increase as we age according to Healthline.

In other words it's just a natural part of life.

LOOK: Things You Saw at Grandma's House

Step into Grandma's house, where cookie tins hold mysteries and even the toilet roll cover has a story to tell.

Gallery Credit: Stephen Lenz

The Least Likely Sequels That Actually Happened

We cannot believe these sequels exist.

More From WFHN-FM/FUN 107