You must have lived under a rock for the last 50 years if you haven’t heard about those chemical text messages called pheromones. Just look around you. No, truly observe. Dogs can’t resist the urge to mark their territory as they patrol the neighborhood. Laboratory mice cower in the corner of their cages when exposed to the smell of cat urine. And, we all know about those pesky mosquitoes drawn to your breath CO2 and body heat.


What we can learn about pheromones from Drosophila

Here is something puzzling and instructive at the same time. The male Drosophila fruit fly emits a volatile substance called CVA (11-cis-vaccenyl acetate) which works its magic on the female fly and makes her enthusiastically submit to his advances. But whatever residue of the aphrodisiac lingers on her body turns off an approaching male and he beats a hasty retreat. It’s the same chemical substance but it has opposite effect. From a natural selection point of view, it makes perfect sense. The impregnated female and the horny male don’t need to waste energy on pointless sex.


Is there a human sex pheromone?

Copulating fruit flies
Even fruit flies do it

In short, the behavior of everything around us is controlled by a symphony of odors. So is it any wonder that investigators have been on the hunt for the elusive human pheromone for the past 50 years? Just Google “human pheromones” and you’d get hundreds of thousands of hits.

Why this intense interest? Because there is money in it. Just go to the perfumes section of any department store and you’ll see the chemical warfare arsenal designed to lure you (if you are a male). Or check out the man-toiletries area of the store where products are hoping females will be captivated by the musk scents of the after-shave lotions. But, does it really work?
Pheromones will improve your sex life, a common sales pitch goes. But despite decades of research and untold millions of dollars, not one chemical has been identified that causes the release of a behavioral pattern. Which brings us to a bit more sophisticated understanding of pheromone effects.

The pheromone hitting the female fruit fly’s antennae caused the release of her receptive behavior; nothing romantic, nothing volitional. It’s all automatic and hard-wired. This type of behavior is uncommon in mammalians. More common are priming effects, in which the physiology of the recipient of the pheromone is changed, without immediate behavioral changes. For this kind of effect, evidence does exist.


We’ve lost our pheromone sense

In a study of menstrual cycle synchronization, a team led by Martha McClintock at the University of Chicago, collected body secretions from women at different times in their menstrual cycles and presented the substance under subjects’ noses. The test subjects either accelerated or slowed their cycles to synchronize with the donors’, even without conscious perception of the odor. However, more recent studies challenge this study, and the phenomenon of menstrual synchronization is disputed, even when women are living together.

Serena williams in action
Serena in action.

The whole idea of human pheromones becomes even more problematic because the machinery that mediates pheromone effects on the brain of Drosophila and mice is barely present in humans. In non-humans, the organ that senses the pheromones is called the VNO (Vomernasal organ), which in humans is vestigial. Which raises the question: Why would natural selection allow the loss of such an important organ?

The answer is quite fascinating. Recent research showed that at about the same time our primate ancestors gained color vision, they also lost the genes for the VNO receptors. In other words, we switched from experiencing the world through a bouquet of odors wafting up our noses to the symphony of colors imprinted on our retinas.

Which is better? I suspect if you asked fruit flies, they would tell you they are quite happy, thank you. For myself, I am very happy to watch a beautiful young woman playing tennis, sans her armpit smell.

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.


  1. All women have a scent – it does not matter size shape or color of the woman and the bravest and best are the ones who let the hair grow on their bodies – who are free and don’t let others decide what is proper or not. If you don’t like it go hide in some other sad place. These women of scent and hair are the most wonderful of all

  2. Haha, yeah, so true. I’m fine with the natural smells of humans:) all those companies would go bankrupt if we all didn’t believe that armpits should smell like perfume~

  3. It’s the major turn-on of all for me. I love even the scent of a woman who is totally unattractive in every other way. I suspect the excessive fetish for showering and shaving every few minutes is connected with guilt about sin – “wash my sins away” is a common phrase.

  4. Most of it is just fetish. I have had women armpit fetish forever. I like the smell, the look and even better when it’s sweety.

  5. There is a place for perfumes, it is called “aromatherapy”. Of course they don’t consider aromatherapy because the cosmetic industry is yet another crappy profit oriented industry.

    As for pheromones, I can often tell when a girl is on her period, which makes me quite “interested” in the girl, but it is not a very “visible” smell, it is more like a sense. It’s a very subconscious sense, and that hasn’t really been considered here…

  6. The cosmetic industry does not want these type of articles and topics discussed by the public , they want them to believe that the armpit should smell like the perfume that they sell, just imagine if everyone believed in pheromones as a natural desired smell what would happen to their billion dollar industry??? The public for the most part has been pre-conditioned into thinking that the natural armpit smell is “gross” which is good for their business…..

  7. Men can absolutely smell a women’s pheromones just as women can men. This is either very poorly researched or a trolled posting. I have done my on thoughts on this and brought them up to many women I know.

    First off what idiot thinks it’s the bloody arm pit?

    Most women well get hit on more often when on their period. Every women I have asked this has thought about that question for a few mins and agreed, just as women love a hard working man you comes home covered in sweat wether it be from actual work or some kind of sport. The scent is stingray with a woman right before and after her period (her most fertile times). Reason women like t when a man comes home sweaty from work or the gym (not because of a few days of not showering) is because of the increase of testosterone in turn releasing that particular scent that attracts women.

    My god… Beginning to think these doctors need to really use common sense. I would love to have an actually Doctor or scientist chime in on this… I love the challenge and I may not have a degree but I have done much research of my own and studying in many areas. I love to learn making me a very formittible opponent, or so I been told!

  8. “Our Ancestors….”

    How amusing. If evolution is to be taken as fact, then there must be hundreds of thousands of transitional fossils proving the phenomenon. Tell me, why have none been found while all the while, the atheistic community and proponents of evolution continue to joyfully exclaim they have found “the link,” (Lucy for example) time and time again, only to discover that their science is not only inconclusive, but conclusive contrary to their beliefs, and yet here we are digging up dinosaur bones, purportedly millions to billions of years old?


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