The Love Hormone: The Chemical Behind Attraction and Lust!

If you Google the phrase “biology of love,” you’ll get a wide range of answers. Needless to say, the scientific foundations of love are frequently sensationalised, and, as with most science, we don’t know enough to draw firm conclusions about every part of the puzzle. What we do know is that chemistry can explain a large part of love. So, if there is a “formula” for love, what exactly is it, and what does it imply?

For decades, scientists in fields ranging from anthropology to neuroscience have asked the same question (albeit less eloquently). It turns out that the science of love is both simpler and more complex than we previously thought.

Consider the last time you met someone you found attractive. You may have stammered, your palms may have sweated, you may have said something extremely inane and spectacularly tripped while attempting to saunter away (or is that just me?). And your heart was probably thudding in your chest. It’s no surprise that for centuries, people believed that love (and most other emotions) came from the heart. As it turns out, love is all about the brain, which causes the rest of your body to go crazy.

The desire for sexual pleasure drives lust. The evolutionary basis for this is our need to reproduce, which is shared by all living things. Organisms pass on their genes through reproduction and thus contribute to the survival of their species.

The hypothalamus of the brain is important in this because it stimulates the production of the sex hormones testosterone and oestrogen by the testes and ovaries. While these chemicals are frequently stereotyped as “male” and “female,” they both play a role in both men and women. As it turns out, testosterone boosts libido in almost everyone. The effects of oestrogen are less pronounced, but some women report being more sexually motivated around the time they ovulate, when oestrogen levels are at their highest.

Dopamine, for example, is the hormone in charge of the vast majority of the brain’s reward pathway – controlling both the good and the bad. We get dopamine rushes from both our virtues and our vices. In fact, when it comes to addiction, the dopamine pathway has received a lot of attention. The same regions that light up when we are attracted also light up when cocaine addicts take it and when we binge eat sweets. Cocaine, for example, prolongs dopamine signalling much longer than usual, resulting in a temporary “high.” In some ways, attraction is similar to an addiction to another person. Similarly, when we become addicted to material goods, the same brain regions light up as when we become emotionally dependent on our partners. And addicts in withdrawal are similar to love-struck people who crave the company of someone they can’t see.

For oxytocin, the story is similar: too much of a good thing can be harmful. Recent research on party drugs like MDMA and GHB suggests that oxytocin may be the hormone responsible for the feel-good, sociable effects these chemicals produce. In this case, positive feelings are taken to an extreme, causing the user to dissociate from his or her surroundings and act erratically and recklessly. Furthermore, the role of oxytocin as a “bonding” hormone appears to help reinforce the positive feelings we already have for the people we care about. That is, as we grow closer to our families, friends, and significant others, oxytocin works in the background, reminding us why we like them and increasing our affection for them.

While this may be beneficial to monogamy, such associations are not always beneficial. For example, oxytocin has been proposed to play a role in ethnocentrism by increasing our love for people in our already-established cultural groups while making those who are different from us appear more foreign. As a result, oxytocin, like dopamine, can be a double-edged sword.

Finally, what is love without embarrassment? Sexual arousal (but not necessarily attachment) appears to turn off brain regions that control critical thinking, self-awareness, and rational behaviour, including parts of the prefrontal cortex. In a nutshell, love makes us stupid. Have you ever done something you later regretted because you were in love? Perhaps not. I’d ask a certain Shakespearean star-crossed couple, but it’s too late for them.

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