The Chemistry of Body Odors: Sweat, Flatulence, Smelly Feet

Ever wonder why certain body odors smell the way they do?

The folks over at Compound Interest took a closer look at the chemical make-up of some of our smelliest body odors.

Today’s graphic looks at the chemical compounds behind a variety of body odours – all of which we all experience at one point or another. Each is a cocktail of many different chemicals, but there are a select few that are major contributors to the distinctive aroma of each – here’s a look at some of the main players.

The Chemistry of Body Odors (InfoGraphic)

Infographic credit (link)

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An interesting observation of this study was the difference between the farts of men and women. Though the small sample size means it isn’t possible to draw definite conclusions, they noted that the women in the study emitted a significantly higher concentration of hydrogen sulfide, and the judges both ascribed to them a significantly worse odour. They also noted that men tended to generate ‘a greater volume of gas per passage’. Now we know.

Underarm Odor

Your underarms are home to an estimated one million bacteria per square centimetre; these convert your otherwise odourless sweat into a variety of malodourous molecules. 3-methyl-2-hexenoic acid (sweaty, goat-like aroma), 3-hydroxy-3-methylhexanoic acid (cumin-like smell), 3-methyl-3-sulfanylhexan-1-o (onion-y smell).

Foot Odor

Two of the other main compounds contributing to ‘cheesy’ feet are propanoic acid & isovaleric acid. Propanoic acid is described as ‘pungent, sour and rancid’

Other Reading

What makes our armpit stink? Read more here.

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