According to the Daily Mail, researchers discovered that individuals over 40 release increased amounts of a chemical known as 2-nonenal, characterized by an “unpleasant greasy and grassy odor.”

The formation of 2-nonenal occurs when skin fats are broken down due to oxidative stress, a process that accelerates as we age and also contributes to skin ageing.

Researchers suggest that consuming mushrooms can help mitigate this odor. Mushrooms are rich in antioxidants, primarily ergothioneine and spermidine, which counteract the “old people smell” by reducing 2-nonenal.

However, getting rid of the smell can be challenging. Experts say that both showering and perfume are ineffective in fighting against 2-nonenal.

Leslie Kenny, co-founder of the Oxford Longevity Project, cautioned: “A challenge in attempting to wash it away is that 2-nonenal becomes embedded in our skin layers, and as skin ages, it sheds this less efficiently.”

“You can’t mask it with perfume. The perfume simply layers on top of it, giving it a musty smell. What you want to do is get rid of it from the inside out.”

She added: “The smell is caused by oxidation of molecules in sebum [the skin’s natural oil]. It’s young sebum that makes babies smell delicious. But in old age, sebum can oxidate and go rancid.

“Studies show that if you don’t have enough antioxidants in your diet, then that smell builds up. What’s more, it can linger because our skin cells don’t replace themselves so quickly when we age.”