The days of smelly armpits may be coming to an end, thanks to new research that has pinpointed the enzyme that causes underarm odour.

When it comes to BO, sweat is not the main issue. The real culprits are the millions of bacteria living in your armpit that produce an unpleasant smell when they come into contact with sweat and start breaking it down.

Until 2015, the assumption was that one of the major components of the underarm microbiome, the corynebacteria, were responsible for triggering the odour. Then new research discovered that a different and smaller group of bacteria was in fact responsible for BO.

“It was a huge shock to discover that only a few Staphylococcus bacteria, including Staph. hominis, caused odour,” remembers Dr Gordon James, one of the Unilever scientists working with researchers from the University of York on the BO project.

Now the team has gone a step further by identifying a unique ‘BO enzyme’ found only within these bacteria and solely responsible for the distinctive note of armpit odour.

“This is the biggest breakthrough yet from our successful collaboration with the University of York on the origins of BO,” says Gordon. “The discovery of a key odour-forming enzyme in a select few bacteria, which evolved tens of millions of years ago, is a real eye-opener.”

What makes this enzyme particularly interesting is that the smell it produces does not seem to have any real purpose. Most ‘bad’ smells our bodies produce work either as warnings of infection or disease, or as a red flag to stay away. BO, however, does not seem to serve any function for us, or for the bacteria which produce it.

This may not, of course, have been the case tens of millions of years ago when, according to the findings of this new research, this enzyme first evolved in ancestral primates, possibly as a biological early warning system of danger.

Key to more targeted products

Body odour clearly no longer serves this purpose, and ever since the creation of the first deodorants and antiperspirants in the late 19th century, we have been trying to suppress it, either by the use of antibacterials or by masking the smell. Now, thanks to the insight offered by this new research, a whole new range of products could be developed to battle BO.

“Most armpit bacteria do not produce much odour, which means at the moment a lot of effort is being spent targeting bacteria that have little influence on BO,” explains Gordon. “With the discovery of this enzyme, we hope to develop techniques that would work by directly inhibiting the odour-forming enzyme at source.”

Would this mean that by eliminating body odour we would also lose our inherent and unique body smell? Gordon is reassuring. Our more attractive body smells are produced by other mechanisms and would not be affected. It would just be BO that we would lose – which is something we can all live happily without.

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