The smell of love and sex is …

The role of hormones in attraction

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The smell of love and sex is …

Today’s the day of love: Valentine’s Day. Whereas some people dismiss it as utter commercial nonsense, for others it’s a day to be honored, as illustrated by the heart-themed items flooding the stores and marketing campaigns flooding our screens. But to celebrate love, it’s not necessary to buy anything. A good tumble in the sack, with or without a partner, brings many benefits (but more on that later). Cursor took a peek under the hood of attraction, love, and sex. Is there such a thing as chemistry? And how come you can smell it when a woman is horny?

photo Fotoduets / iStock

So why did we pick February 14 as the day to celebrate love? And why is it called Valentine’s Day? As there are several stories going around, we don’t have the definitive answer for you. One of the most common explanations is that the name derives from the Christian priest St. Valentine of Rome. Legend has it that at the time, an imperial law was in place prohibiting soldiers to get married, because bachelors were believed to be more prepared to die in battle. But St. Valentine is said to have wed soldiers in secret, as he thought loved conquered all. When Emperor Claudius II found out about this, he had the priest executed on 14 February 269, making Valentine a martyr for love.

Cupid is not commemorated specifically, but was the Roman god of love or lust. According to ancient myth, whoever is struck by an arrow will fall in love with the first person they see. This is why Cupid symbolizes luck at first sight and often adorns Valentine’s Day cards. All-in all it would appear the Romans ignored the olfactory aspect of physical attraction.

Chemistry in love

Does ‘chemistry’ really make us fall in love or is that a thing from the movies? Which hormones contribute to physical attraction? Professor of Chemical Biology Luc Brunsveld opened his pharmacology textbook for the occasion. This gave Cursor something to work with, as it turns out fact-checking online information in this specialized area is pretty difficult for journalists without a chemistry or biology background.

Anyway, without further ado: yes, chemistry is involved in attraction. “It’s a combination of different types of molecules, such as dopamine, serotonin, noradrenalin, oxytocin, testosterone, and estradiol. The roles and ratios of the molecules varies according to the stages of love (initial/lust/bonding-oriented attraction/attachment),” Brunsveld teaches us.

Via the nose

With around 17 million people living in the Netherlands alone, we should probably be happy we’re not attracted to everyone. You wouldn’t get much else done. But what singles out those exceptions among the crowd that do give you that special feeling in the pit of your stomach? Smell turns out to be a major ingredient. A smell is the sensory stimulation of the olfactory membrane in the nose by a cluster of molecules. There are certain body odors that play a role in human sexual attraction, a subconscious process in which people use a potential partner’s body odor to determine whether they will pass on positive traits to the offspring. So body odor can provide us with important clues about the genetic quality, health, and reproductive success of that potential partner. Brunsveld: “But that doesn’t mean that if someone is too far away to smell them, there’s no attraction by default. There are simply too many aspects at play when it comes to physical attraction. And the ratios of the molecules involved also change as it passes through its different stages (initial/lust/bonding-oriented attraction/attachment). Testosterone and estradiol in particular are very powerful molecules that are not only key in the development of secondary sexual characteristics, such as breast tissue and a wider jawline, but also determine your sex drive. If you have more testosterone, you generally have a higher sex drive.”

There are a few different ways in which body odor influences sexual attraction, including via human biology and the menstruation cycle. The olfactory membrane plays a role in smelling and subconsciously judging other’s people’s pheromones. This is not unique to humans, as it also happens in the animal world.

For example, research has shown that for heterosexual women body odor is strongly linked to physical attraction. One study group of women even deemed body odor a more important aspect of attraction than looks.

The smell of arousal

You can smell it when a woman is aroused. Really, you can. Research even shows that men can pick out women who are in the mood for sex, based on the hormones they secrete. Maybe on past occasions your partner mentioned that they could smell you were in the mood? Or maybe you yourself know what you smell like when that happens? What’s not yet clear, is how women produce this smell. “It’s probably a mixture of hormones (such as estrogen, oxytocin, and testosterone) that are already related to sexual arousal,” researcher and Lecturer in Psychology Arnaud Wisman (University of Kent) said in explaining his research to science magazine Scientias. “If we had an exact formula for this hormone mixture, I think the perfume industry would already be knocking at our doors.”

Men also emanate smells that can cause physical attraction. “For instance, their sweat contains increased concentrations of the steroid metabolite androstanol, which appears to be an attractive smell for heterosexual women,” says Brunsveld. “But when the sweat remains on the body for too long, the compound oxidizes and it turns into a repulsive smell.”

Point of no return

When you’ve found a match in terms of physical attraction and decide to go for it, the general hope is for the sex to lead to an orgasm. Or multiple orgasms. But is an orgasm just a muscular spasm or is there more to it? “There’s definitely more to it,” Brunsveld says. “An orgasm doesn’t only make your muscles spasm, it also dilates your pupils and raises your hormone level in terms of dopamine, oxytocin, and serotonin. Your heart rate and blood pressure are increased. During those orgasmic spasms, the hormones are basically running rampant in your body.” This means an orgasm can be relaxing and stress-reducing. So in addition to feeling nice, an orgasm can have positive long-term effects as well. Happy Valentine’s Day!

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