Israel’s Weizmann Institute of Science conducted a study that seems to suggest that, even having no apparent odor, women’s tears kill male libido. Pheromones are believed to be the culprit.

Tears triggered by emotions are not of the same chemical makeup as tears triggered by foreign objects in the eye. So far, only women’s tears have been studied, as the volunteer demographic proved collecting sorrowful tears from men to be much more difficult.

The study was conducted with real tears collected during a sad movie, with the control group exposed to saline drops collected in a similar manner. The groups were reversed for the next test, and following double-blind protocol. The study also tested the ability of healthy males to distinguish between the tears and saline solution.

Men exposed to the real tears were determined to have lowered testosterone levels after exposure. The study also found less sexual attraction when exposed to women’s photos than just sniffing salt water.

Subsequent testing revealed that exposure to the tears lowered aggression, which is an element of sexual arousal, but did not increase empathy. This was concluded by MRI testing while subjects watched a sad movie.

“Communication isn’t limited to language,” said neuroscientist Noam Sobel, whose study was published online Thursday by the journal Science. “And here, we’ve uncovered the chemical word for ‘no,’ or ‘not now.’ “