The notion that our body odors are potent, chemically charged mating signals—so-called pheromones—is so pervasive in women's magazines and websites, you would think that all you need is one good sweat to lure your guy. This spring, Shape magazine proclaimed that working out together fires up a relationship, because when you're hot and sweaty, "you continue to release attraction-boosting pheromones for an hour after you finish exercising." Want to turn an ordinary dinner date into "incredibly hot sex"? All you have to do, according YourTango, a love-advice website, is avoid putting perfume on your neck, breasts, or genitals, because that "hides the important pheromones that drive men wild." Last year, Cosmopolitan—another go-to source for medically oriented dating strategies—suggested you go panty-free so that the "odors in your pheromones—that natural chemical you emit that attracts men—may more easily waft into the air to be picked up subliminally by the primitive part of his brain."
If only it were so. Pheromones, in scientific parlance, are aromatic chemicals emitted by one member of a species that affect another member of the same species, either by altering its hormones or by compelling it to change its behavior. When they work, they are truly bewitching. For instance, when a female silkworm moth wants to get her guy, she sprays a chemical called bombykol from her abdominal gland and her targeted male transforms into a sex slave, trailing the scent until he mounts her. It's an enviable feat. Still, it's a big leap to extrapolate from bugs to people—or even to lab mice, for that matter. No scientific study has ever proven conclusively that mammals have pheromones.
"The whole pheromone thing got picked up by the mass media," says Richard Doty, director of the University of Pennsylvania's Smell and Taste Research Center and author of The Great Pheromone Myth. It feeds into our need to believe, he said, that there "is all this subliminal stuff going on that is affecting us—who we mate with, who we want to be with. It's this mythical perspective." And marketers, like women's magazines, are only too happy to exploit that myth. That's how a whole junk-science industry of pheromone-perfumes, pheromone-soaps, and pheromone-cosmetics managed to spring up from a strange menagerie of misconstrued mammal studies.
About 50 years ago, Richard Michaels, an English psychiatrist and primate researcher, claimed to have found chemicals in the vaginas of rhesus monkeys that attracted males of the species. He and his colleagues called the substances copulins, as in "copulate." Soon thereafter, Michaels released a patented copulins recipe—a blend of vaginal aliphatic acids, based on the monkey secretions—which has since become the basis for most women's perfumes and soaps that claim to include "pheromones" that attract the opposite (human) sex.
But even Michaels realized that the sense of smell might only be a minor factor in mate selection. In a subsequent study, published in the Journal of Endocrinology in 1982, he paired a dozen male rhesus monkeys with four females apiece. Some of the females had copulins rubbed on their vaginas; some had placebo. Researchers then counted how many times each female was mounted. All the females had their ovaries removed, to wipe out the effects of natural hormones that could confound results, and were given estrogen, thought to enhance the actions of copulins. Still, the study found that the vast majority of males were not influenced by copulins. In fact, they were more often swayed by the presence of a dominant female than by smell alone. (The alpha female would literally block the male's access to the other three monkeys.) Meanwhile, the few human studies on the topic have tried to determine whether male volunteers wearing surgical masks coated with lab-made copulins were more aroused by photos of women than were volunteers wearing placebo-coated masks. They weren't.
The other so-called human pheromone that shows up in body care products is androstenedione, a chemical found in sweat. Androstenedione has been making the media rounds for years. Initial research in the early 1990s suggested that women were aroused by its musky smell, but later studies complicated that notion. One famous study from 1995—in which women were asked to sniff a bunch of sweaty T-shirts and choose the one they found most appealing—suggested that it wasn't the chemical itself that attracted women, but the way it mixed with a man's genes. (The women tended to choose T-shirts from men whose immune systems were most different from their own, suggesting that humans have an innate smell-based system to avoid mating with siblings.)