Professor Matthew Cobb

This is a consequence of your muscle physiology and sweat's primary function is to cool you down.

Some of those physiological byproducts have, to humans, a particular odor, which we would give a particular valence or meaning to or value to.

And that will differ in different cultures.

And then very quickly, your microbiome is going to start metabolizing some of those physiological byproducts.

They're going to eat your sweat and they're going to crap out various other products, which we might not find quite so attractive.

But again, this is going to vary hugely between cultures.

You know, in colonial India, the British all wrote that the Indians smelt.

And the Indians all wrote that the British smelt.

So we use odour as a way of putting on to existing social differences.

George Orwell famously said that he learnt at Eton that the poor smell.

So you've got this value associated with odour, which is not simply objective.

It's also to do with kind of cultural norms and cultural significance and how you can other odour.

I don't think it's true.

I mean, these signals are called pheromones.

Say, in a pig, the male produces a substance called androstenone that changes the behaviour of the female, actually gets her to start producing eggs so they can then mate.

Yeah.

These signals, these pheromones, there is no evidence in humans that we have the genetically based signal that says I'm fertile or I have a particular immune system.

People have been studying this for a long, long time.

And the evidence is flaky to say the best.

And there is no identified compound there.