By Veronica Grignano
Love. A warm and dreamy emotion, somehow opposing any rational thought. The telltale signs of being in love, rosy cheeks and a fluttering heart, couldn’t seem farther from anything science-based. But, beneath flushed cheeks and dreamy smiles, lie a series of complex chemical reactions that make up the “formula” to love.
Scientists have determined that love can be broken down into three primary categories: lust, attraction, and attachment. Each category is defined by a set of hormones released by the endocrine system and controlled by the brain—yes, the brain. Typically, the heart is thought to be the emotional centre of the body. However, in reality, your brain is behind all of your stupefying feelings of infatuation.
Lust is categorized by the desire for sexual gratification. As such, this form of love is driven by the sex hormones, testosterone and estrogen. These hormones are incorrectly thought to be gendered, with testosterone impacting men and estrogen impacting women. However, testosterone increases lust in just about everyone, as does estrogen, although to a lesser degree. Testosterone and estrogen are produced in the testes and ovaries, respectively.
Attraction is another category of love, driven by the reward centres of the brain. Dopamine is one of the most well-known “reward” hormones, and the main component of the attraction phase of love. This chemical is produced by the hypothalamus, a region of the brain, and is released when you do something you like! This can be anything from spending time with a loved one or participating in an activity you both enjoy. Scans of people in love demonstrate increased neural activity in the brain’s reward centres when people are shown a photo of someone they love. In contrast, neural activity decreased when the same individual was shown a picture of an acquaintance. A related hormone, norepinephrine, is also released during attraction. Coupled with dopamine, these two chemicals make us feel energetic and giddy, the reason why true love is often described as “intoxicating.” The relationship between attraction and a desire for a dopamine or norepinephrine release demonstrates why new relationships can be both exhilarating and obsessive. The infatuation of attraction often fades away as relationships mature and the body builds tolerance to pleasure stimulants.
Finally, attachment comprises the foundation of most successful long-term relationships. While lust and attraction are almost exclusively romantic feelings, attachment is present throughout any and all forms of love: familial love, platonic love, and romantic love! The two hormones that dictate attachment are oxytocin and vasopressin. These chemicals are released during bonding activities, reinforcing positive feelings towards our friends, family members, and partners. On a biological level, oxytocin and vasopressin support the vigilance required to defend a spouse or territory. Oxytocin is also linked with increased immune function, supplementing the idea that happily married couples see an increased lifespan, and a decreased risk of heart attacks, strokes, and depression.
However, love should not always be looked at through rose-coloured glasses. Jealousy, obsession, and irrationality often accompany the more pleasurable feelings related to love. After all, there is a reason why love is often described as a sickness. In fact, too many of the “love hormones'' can have negative effects on an individual’s physical and mental health. Too much dopamine and norepinephrine—the same chemicals that produce warm and fuzzy feelings—can lead to decreased appetite and insomnia. As a result, you can be so in love that you cannot eat or sleep!
Love can also quickly turn sour: obsession and unhealthy attachment to an individual are not as uncommon as it may seem. Dopamine, controlling the brain’s reward system, is the primary culprit behind addiction. The same regions of the brain that fire when someone uses a drug, purchases an expensive item, or eats their favourite food, also light up when we see someone we love. Thus, attraction is comparable to an addiction to a loved one. Pure, innocent love can easily venture into an emotional dependency on one’s significant other.
Similarly, oxytocin acts as a double-edged sword. The chemical’s role as a “bonding” hormone serves to reinforce existing positive feelings and opinions toward a familiar individual. This effect is usually positive, as oxytocin allows us to continually increase fondness toward our family members, friends, and significant others. However, this can also reinforce ethnocentrism and the idea of the “out-group.” As our love for our established cultural group grows, those different from us grow increasingly foreign.
As unromantic as it may seem, the infatuation you feel toward someone you love can be boiled down to bodily hormones. However, much is yet to be discovered about this fascinating, mysterious, and thought-provoking topic. There is no denying that love has a creative and whimsical aspect to it as well. And that might very well be the best part about love! Love is not a one-size-fits-all experience. It is filled with highs and lows, smiles and tears, and plenty of hard work. If love was only about chemistry, each relationship would be a cookie-cutter mould of the last. But the uniqueness of each relationship is what makes love such a special and wonderful experience.
Works Cited
Powell, Alvin. “Scientists Find a Few Surprises in Their Study of Love.” Harvard Gazette, 23 Jan. 2019,
Sayer, Lizzie. “The Science of Love.” International Science Council, 13 Feb. 2020,
Wu, Katherine. “Love, Actually: The Science behind Lust, Attraction, and Companionship.” Science in the
News, 19 June 2020, sitn.hms.harvard.edu/flash/2017/love-actually-science-behind-lust-
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