Why do our armpits smell? Researchers 'discover molecule that causes body odour'

A team of scientists have conducted pioneering research into the science of body odour that could one day lead to more powerful protection against underarm embarrassment.

Researchers at the University of York have made new genetic discovery regarding the Staphylococcus hominis, pinpointing the bacteria as the main offender in making armpits pungent by breaking down naturally secreted sweat molecules.

They inhabit the temperate climates of your underarm microbiome and there are more of them in your pits alone than there are humans living on the planet. What actually smells are thioalcholols, an organosulphur compound that the bacteria produce from ingesting your sweat.

Scientists Daniel Bawdon and Gavin Thomas of York, alongside Gordon James and Diana Cox of Unilever, investigated the gene encoding proteins responsible for producing free thioalcohols.

The researchers took bacteria commonly found in the armpit and added an odourless molecule found in human sweat. As explained by Bawdon: “Those odourless molecules come out from the underarm, they interact with the active microbiota, and they’re broken down inside the bacteria.”

Of all the bacteria under the armpit the Staphylococcus hominis were the worst offenders, but there are a variety of Staphylococcus species that produce thioalcohols to a lesser extent.

The thioalcohols have a scent comparable to sulphur, onions or meat when concentrated.

Referring to the potential that the findings could have in preventing the production of bodily odour, Thomas says: “It makes sense not to kill everything. As we know from antibiotics, if we can design something specific that’s probably going to be a more sensible approach.”

Thus the team envision a deodorant that would prevent armpit bacteria from producing thioalcohols rather than simple killing them off.

Currently deodorants can temporarily prevent you from sweating, mask the smell with other fragrances or eliminate some of the odour by nonselectively killing bacteria.

But before such a deodorant could show up on shop shelves however, the researchers need to make sure that there aren’t more smelly processes taking place in the armpit.

There could be more molecules making the armpit produce odours and they haven’t concluded their studies yet: “It’s an extremely exciting time to be a microbiologist”, says Thomas, “We haven’t really figured out why they’re there and exactly what they’re doing.”