Why Do We Love? The Chemistry, Biology, And Evolution Behind Love

Medically reviewed by Karen Foster, LPC
Updated April 30, 2024by BetterHelp Editorial Team

Love has been studied often and featured widely in countless forms of art, but it often feels like it is, in some ways, still shrouded in mystery. What exactly is love, what does it feel like, and why does it exist in the first place? Love can be blissful, wonderful, complicated, and confusing. Here, we’ll explore some of the chemical, biological, and evolutionary aspects of love.

Love can be confusing sometimes

What is love?

The American Psychological Association defines love as “a complex emotion involving strong feelings of affection and tenderness for the love object,” as well as positive sensations in their presence, care for their well-being, and sensitivity to their opinions.

Love is often described as an emotion that develops in a relationship between two or more people and which takes on many different forms, such as the love between parent and child, romantic partners, close friends, for oneself, and more.

In emotional terms, love often means considering the needs, feelings, and hopes of the people you care for. Love can be the driving force behind the tears that come to your eyes when your child first learns to walk and the emotion behind the tears that pour when a loved one has passed on following a long illness. 

But, beyond these definitions, how exactly does love work? Let’s explore some of the chemistry, biology, and evolutionary aspects of love. 

Love and chemistry: Your brain in love

When you think of your brain and how it perceives love, you might think of your thoughts racing, how consumed your mind seems to become with your significant other, or how easy it is to daydream about having a future together. From a chemical perspective, there is a lot going on, too. According to a team of researchers, romantic love can be broken down into lust, attraction, and attachment, which each have their own set of hormones: testosterone and estrogen drive lust; dopamine, norepinephrine, and serotonin drive attraction; and oxytocin and vasopressin drive attachment.

Love and biology: Your body in love

There are also some changes in the body that can occur when romantic love has arisen. For instance, love can slow your heart rate and decrease your blood pressure, it can provide pain relief, and it can even affect your taste buds. One study found that people who were induced to feel love rated a variety of tastes as sweeter than those who were instead induced to feel jealous, neutral, or even happy. In addition, feeling attracted to someone can also cause your pupils to dilate, and the early stages of an intense crush may cause you to have trouble sleeping.

Getty/MoMo Productions

Love and evolution: Your motivation in love

From the perspective of evolution, love may exist as a motivator with an adaptive benefit. Love can encourage people to procreate, contributing to the perpetuation of the human species. In this way, love can be more than chemical reactions, emotional experiences, and bodily effects. Love can play a key role in keeping the human species alive and can be an evolutionary mechanism driving humankind’s survival. According to some researchers, love is actually a “complex suite of adaptions, designed to solve specific problems of survival and reproduction.” In addition to romantic love, love for others such as friends and family can also contribute to strong social connections, which can have a range of positive health benefits.

Within this idea, though, there is plenty of room for nuance. Love impacts people differently, has different physical and emotional symptoms, and is impacted by far more than just evolutionary biology. While love may be an adaptation, this does not mean the effects and feelings it generates are not real. Instead, it means that love may also have a specific driving purpose. Love can have a role in our species’ survival, but it can also be responsible for many of the aspects of life that humans treasure and find meaning and purpose in.

Help with love through therapy

Love can be joyful, exciting, scary, and confusing, and it can be difficult to navigate on your own sometimes. If you would like additional support with understanding love, cultivating it in your life, and making sense of its effects, a therapist may be able to help. 

Love can be a very personal and very vulnerable topic to discuss, and some people may find it helpful to be able to talk with a therapist about sensitive matters of the heart in a space that feels familiar and comfortable. With online therapy through BetterHelp, you can meet with a therapist from the comfort of your own home.

Love comes in many forms and it can involve and affect many areas of our lives. Whether you’re grappling with low self-love and its effects on your mental health, complicated love for a parent and its effects on other relationships, or heartbreak from a recent breakup and the toll it’s taking on your life, online therapy may be a good option. Research has shown that online therapy can be effective for a range of concerns and that online therapy can be just as effective as in-person sessions.

Love can be confusing sometimes


Love can have wide-ranging effects on the brain and body, and it may serve an important role in the perpetuation of the human species. While love can be filled with happiness and excitement, it can also be confusing, scary, and painful at times. If you would like support in navigating the many aspects of love and understanding its role in your life, online therapy may be able to help.
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