Across parts of the internet where young men trade tips on self-improvement, the latest project is scent.
Deodorant is out and washing less is in.
Many animals communicate with pheromones, often around sex or marking territory. The problem is what happens when you look for the same sensory hardware in humans.
A pheromone is a chemical messenger made inside the body of one member of a species, such as a cat, that's secreted or excreted and produces a response in another member of that same species.
Pheromones were first identified in silk moths back in 1959.
A male silkmoth exposed to this pheromone will beat his wings and walk upwind toward the source.
Other animals, such as mice, pigs and cats, release and can sense pheromones. The purpose is usually to attract a mate or mark territory.
A pheromone isn't defined by whether you can smell it or by which organ picks it up.
Some pheromones are volatile and smellable. Bombykol, for example, is detected by ordinary smell receptors on the moth's antennae.
Not whether it has a fragrance.
For a pheromone to be functional, something has to be able to receive it.
In many four-legged animals, that job falls to the vomeronasal organ, a small structure in the nasal cavity.
What's more, no chemical has ever been found in humans that meets the criteria to be labelled a pheromone.
Sweat is just a mix of 99 per cent water, electrolytes and then small amounts of urea, ammonia and other compounds.