LIANE HANSEN, host:
This month is the 50th anniversary of the creation of the word pheromone. Pheromones are chemical signals that animals use to communicate with each other, often about sex. NPR's Nell Greenfieldboyce examines whether humans have pheromones and the online sales of supposedly pheromone-based potions.
NELL GREENFIELDBOYCE: If you go to Google and type in human pheromone, you will get hundreds of thousands of links.
Dr. TRISTRAM WYATT (Pheromone Researcher, University of Oxford): And most of them are trying to sell you something.
GREENFIELDBOYCE: Tristram Wyatt studies pheromones at the University of Oxford.
Dr. WYATT: The idea that there is something you can splash on yourself to make you irresistible is the ever-enduring hope.
GREENFIELDBOYCE: At least since scientist identified the first known attractant, a chemical sent out by the female silk moth to lure males to her. Its discovery five decades ago led scientists to coin that new word - pheromone.
Dr. WYATT: It was built up from two Greek words, hormone for excite, and pherein for transfer. So it's excitement transferred from one individual to another.
GREENFIELDBOYCE: Wyatt wrote an essay for this week's issue of the journal Nature that reviews what researchers have learned since the invention of the word. He says there is no doubt that a lot of different animals, including mammals, use chemical signals. But he says no one has identified anything like that for humans, but not for lack of trying. Wyatt says back in the 1980s and 1990s, various chemicals were proposed as being the, quote, "human pheromone." A bunch of them belong to a family of steroids related to testosterone.
Dr. WYATT: But there is no good evidence that these actually are the human pheromones. The evidence is always circumstantial and rather poor.
GREENFIELDBOYCE: If someone tries to sell you a jar full of something called a hundred percent human pheromones, I guess as a scientist, what's your reaction to that?
Dr. WYATT: Well, I'm afraid it's wasted money.
Mr. BILL HORGAN (CEO, Human Pheromone Sciences): My name is Bill Horgan. I'm CEO of Human Pheromone Sciences.
GREENFIELDBOYCE: Human Pheromone Sciences is based in California, and for 50 bucks it will sell you a blue bottle of what it calls pure human pheromones. Horgan says a key ingredient is one of those chemicals related to testosterone.
Mr. HORGAN: The androstadienone is found in the human body, and people who are exposed to it - men and women - indicated a feeling of warmth and lack of negativity, improved positivity.
GREENFIELDBOYCE: He says his products affect the person who wears them.
Mr. HORGAN: They're not sexual attractants. That's a key thing that we try to get across.
GREENFIELDBOYCE: His company's Web page, NaturalAttraction.com, does say that, quote, "Human pheromones are gender-specific, naturally occurring substances that trigger specific mating responses." I told Horgan the scientist I'd talked to said no chemical had ever been proven to be a human pheromone. Horgan insisted that studies show his products can produce pheromone-like effects on mood and behavior.
Mr. HORGAN: We've seen it and others have seen it, independent of us. In fact, some of them were detractors of us at first - they didn't believe it - like the Monell Institute.
GREENFIELDBOYCE: The Monell Chemical Senses Center is a nonprofit institute in Philadelphia and one of the top centers for smell research. Horgan said a researcher at Monell named Charles Wysocki had done a study. And Horgan sent me the report. It said the chemical in his product had produced courtship-like behaviors in women.
So I called Wysocki. He said, oh, that study. It was done years ago. He said he had his doubts at the time about the design, the analysis of the results, and his collaborators' far-reaching conclusions made him uncomfortable, to the point where he asked to have his name taken off the paper. I sent Horgan an email telling him that. He expressed amazement and said the science behind his company's products is supported by other researchers. Wysocki says if someone is trying to sell you a bottle of human pheromones...
Dr. CHARLES WYSOCKI (Biologist and Psychologist, Monell Chemical Senses Center): I'd be very skeptical. Caveat emptor.
GREENFIELDBOYCE: Now, Wysocki does believe that body smells can influence other people in various ways. For example, he did one well-controlled study. He did blood tests on women who sniffed samples of male underarm odor.
Dr. WYSOCKI: We did see an alteration in the hormone system that regulates the menstrual cycle.
GREENFIELDBOYCE: But he doesn't know what in men's body odor was causing that.
Dr. WYSOCKI: What we are lacking is the actual chemical identities. That's where chemistry has to catch up with the behavior and the endocrinology.
GREENFIELDBOYCE: He's trying to find those chemicals. But even if he did identify a human pheromone, Wysocki says whatever effect it had would be subtle - nothing like the irresistible sex lure that scientists found in moths decades ago. Nell Greenfieldboyce, NPR News.