Anyone who has clicked with a lover knows that there is something in the air that causes a most delicious attraction–a certain “chemistry.”

Now we know: one element of this is a chemical in a man’s sweat.

At the University of California at Berkeley, researchers asked undergraduate women averaging 21 years of age to sniff men’s sweat. Specifically, they took a whiff of androstadienone, a male chemical signal already known to cause sexual arousal, an enhanced mood, and an elevated heart rate in women. A derivative of testosterone, this musky-smelling compound is also found in saliva and semen.

Some 15 minutes after sniffing this stuff in a jar, the 48 women participating in the study had an elevated level of cortisol, a hormone that keeps one aroused and feeling good and helps people cope with stress. As a control, the women also smelled yeast in a jar, which did nothing to them. (That’s a relief!) The study was published in the Journal of Neuroscience and was led by Claire Wyartm, a postdoctoral fellow at Berkeley.

This adds further credence to the idea that pure chemistry might be a major element in the great mystery of why two people can have an explosive, wild, unexplained attraction. If true, then we may be more like rats and other animals than we thought, driven by chemicals as much as by a shared love of, say, Arctic Monkeys, Shakespeare sonnets, and sea kayaking.

I don’t know about you other men, but today, Valentine’s Day, I’m not going to forego the flowers or perhaps a stanza or two of poetry. But should I skip a shower? This might make me dangerously pungent … or it could be just the trick.