For decades, scientists have been trying to isolate a human pheromone. But while the possibility of tapping into unconscious chemical signals might be a popular one, it’s far from becoming a reality.

TRUTH: Pheromones are real.

The word “pheromone” was coined in 1959 by scientists Peter Karlson and Martin Lüscher. A portmanteau of the Greek pherein (“to carry”) and hormon (“to excite”), it referred to chemical signals emitted and detected by members of the same species. Scientists have since identified pheromones in insects such as silk moths and termites, as well as non-insect species, including mammals and primates.

MYTH: Scientists have identified human pheromones.

To date, studies have shown that exposure to human sweat and secretions can trigger hormonal responses in other humans. For example, in 2011, researchers at Florida State University observed a surge in testosterone among men who were exposed to women who were ovulating. Still, there’s currently little evidence that human-produced chemicals can induce consistent behavioral responses.

TRUTH: They can induce powerful reactions … in certain species.

For insects and animals, pheromones convey important information, including messages about reproductive availability and status. For example, in a recent study, researchers at the University of Tokyo recently showed that the presence of a male pheromone in mice enhanced sexual behaviors in females. In other males, the pheromone triggered aggressive behaviors. The findings were published in Neuron.

MYTH: You can “smell” them.

Many pheromones are released through secretions that have a smell—sweat, for example. But pheromones are not odors, and not all of them can be smelled. Researchers have since tried to distinguish between the effects of scents and pheromones. Consider, for instance, research that suggests human infants have a tendency to follow the scent of their mother’s breast. Might mothers release pheromones to attract their offspring? It’s equally plausible that infants are simply attracted to their mother’s unique personal scent, which is made up of numerous chemical compounds and influenced by diet, genetics, environment, and health factors.

TRUTH: There are two types of pheromones.

“Primer pheromones” cause changes in physiology that happen over time, while “releaser” or “signaling” pheromones induce spontaneous behaviors, such as aggression or mating. In both cases, the action is carried out without conscious knowledge of it.

MYTH: Pheromones are processed by the olfactory system.

In the ongoing search for a human pheromone, one of the major inconsistencies is that pheromones are not typically detected and processed by the olfactory system. The vomeronasal organ (VNO) is a separate structure found in many animals. Located above the roof of the mouth, the VNO detects liquid-dissolved chemicals. It’s the organ that allows animals such as dogs to “smell” each other by licking body parts. It’s also the only organ currently known to be involved in pheromonal communication. But humans don’t have one.

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