The Gym's Aphrodisiac

Sweat, Chemosignals, and Pheromones

Is working out an aphrodisiac? Is the smell of sweat a turn-on? Is there a way to tell if your gym crush is in the mood? Let’s ask science.


People communicate in nonverbal ways. One of the most interesting avenues is via chemosignals: chemical signals transmitted in bodily secretions, like sweat. For example, we can literally smell fear, although our awareness of that communication pathway is largely subconscious. Once science figured this out, the totally obvious follow-up questions were:

  • “Can we smell when a woman is turned on?”
  • “Does man-sweat make women horny?”
  • “Can you, in effect, make your own aphrodisiac?”

Is She Horny? Lemme Sniff Her Pits

For this mini-meta study, the researchers needed some horny women and a handful of guys willing to sniff their sweat. (That had to have been an interesting classified ad.) Sure enough, 11 women and 24 men volunteered to be lab rats.

The females were instructed not to wear perfume or deodorant. Also, they weren’t allowed to be in the test if they were using chemical contraceptives. The scientists were worried that the pill might inhibit these natural chemosignals and negatively affect their sex drives. (It can.)

To begin this weird study, the women first had cotton pads taped to their armpits. Then they cycled on a stationary bike for three minutes at 80% intensity.

Next, they were divided into two groups. Each group watched a different film clip and answered questions afterward.

  • Group one, the neutral-condition group, watched part of a boring documentary about bridge building. None reported feeling titillated. Sorry, History channel.
  • Group two watched a 20-minute clip from an erotic movie called “9 Songs,” which featured unsimulated sex. It also had a plot, but who needs that, right? So the researchers edited out everything but the sex scenes. Sure enough, the clip really buttered their biscuits. All the women reported feeling frisky after viewing it.

The cotton pads were collected from both groups, divided up, and presented later to the sweat-sniffing males in randomized order.

The Results

All the men rated the armpit sweat of the aroused women as more attractive. As a result, the men experienced an uptick in their own “sexual motivation.” The same men didn’t feel any tingling in their special parts after smelling the sweat from non-aroused women.

The researchers concluded: “Men are sensitive to the olfactory signals of sexual arousal released by women. These signals, released along with corresponding visual and auditory expressions of sexual interest, can produce a stronger overall signal that increases sexual motivation.”

In other words, concupiscent women release a particular scent via their sweat that men can sense. When men register that signal, they get pretty turned on too.

Does Man-Sweat Turn Women On?

The science of pheromones (scented sex hormones) is debatable, with some researchers saying that humans can’t detect them and others saying that some humans can detect them some of the time.

Women are sensitive to male pheromones, particularly around ovulation, at least if they’re not using sexually-blunting oral contraceptives.

In one study from The Journal of Neuroscience, women smelled swabs of androstadienone, a constituent of sweat, and a placebo. Researchers measured body temp, skin conductance, pulse, blood pressure, respiratory function, and cardiac rate. Those women who sniffed androstadienone displayed more signs of sexual arousal and even reported a better mood.

But not all male pheromones are the same. The pheromone androstenone isn’t the same as androstenol. Fresh male sweat produces a scent of androstenol, which is attractive to women. But after around 20 minutes, that sweat gets oxidized, becoming body odor. Fresh sweat good, old sweat bad.

Men with higher testosterone levels give off more of these pheromones. So, fresh sweat from a low T male may not be as arousing as sweat from a high-T guy. Also, the oxidized sweat of a high-testosterone dude probably smells worse.

Other research shows that only around 70 percent of men and women can detect these chemical signals. Thirty percent smell nothing, possibly because of a missing gene. Based on DNA samples, those who can smell androstenone were found to have genetic variations in a single odorant receptor (OR7D4).

Lastly, the pheromone firepower may only work at close range. One experiment showed that pheromones could only be detected at a distance of about 18 inches.

Horny Sweat and Mommy Sweat

Men’s sweat smells different when they’re aroused, and women can unconsciously tell the difference according to another study from The Journal of Neuroscience. The researchers collected the armpit sweat of men as they watched either erotic movies or non-erotic movies, then had women sniff the sweat while their brains were monitored with MRI. The “horny sweat” lit up different areas of the women’s brains.

Another weird one: Half of the female test subjects in one study were asked to wipe their upper lips with cotton pads soaked in the sweat of nursing mothers. (The placebo group did the same but with benign smelling pads.) Those given the sweaty pads of breastfeeding mommies reported a 42% increase in desire for their hubbies and boyfriends. Single women even reported more sexual daydreams.

Does scent trigger primitive breeding instincts? Seems that way.

The Mating Instinct and Cortisol

Here’s another possible reason that sweating, or the result of frequent exercise that causes sweating, may trigger female arousal.

Males who burn 200 or more calories a day by exercising reduce their chances of impotence. Exercise also decreases stress, which contributes to erectile dysfunction and infertility.

Behavioral ecologist Fhionna Moore concluded that women prefer men with low levels of the stress hormone cortisol. Instinctively, females seem to know that high-cortisol men have suppressed reproductive function. That’s not an attractive sign that a man would make a good baby-maker or provider. Like it or not, the base functionality of our brains still operates at that level. Sorry, feminists.

Much of what we think of as “attractive” is rooted in rather primitive-sounding mating signals. Certain physical features we think of as “hot” are actually just fertility indicators: youthful looks, full breasts, engorged lips, a muscular male butt, etc.

So women may be unconsciously attracted to men who sweat through exercise because it signals that these guys are less likely to be impotent and would make better candidates for pair bonding and procreation.

Or Is It All In Your Head?

Studies on perfumes and colognes generally show they have no real effects on the opposite sex. But they do affect the wearer. If the scent makes the man or the woman feel sexier, they’ll behave differently, consciously and unconsciously.

A woman who wears a scent that makes her feel sensual may act sexier, indirectly increasing her attractiveness. The same could be said about man-sweat. If you think your fresh sweat turns women on, you may act more confident and sure of yourself, which does turn women on.

If you buy one of those questionable “pheromone” colognes, it may work for you, but probably because you THINK it works and will behave differently.

What Conclusions Can We Draw?

  • If a woman is both aroused and sweating, men can detect it.
  • The smell of fresh male sweat does seem to lead to arousal in females, at least if they’re ovulating, not on oral birth control, have the right genes, and get close to you.
  • The smell of old sweat is just gross.
  • Your lady friend will be friskier after being around a nursing mom and her infant.
  • Being in good shape and feeling confident probably has more to do with your attractiveness than your excretions, but it’s good to work up a sweat anyway because, you know, fitness and stuff.


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