What Love Does to the Brain

The Science Behind the High

Jun 27, 2025, 13:00

They say love makes you blind. And sometimes foolish. Sometimes brave. Often euphoric. Almost always irrational.

If you’ve ever looked back at a romantic memory and wondered, What was I thinking? — the answer might be: you weren’t. At least, not in the way you usually do.

Because falling in love doesn’t just change how we feel. It changes how we think, how we judge, and even how we see the world. The reason? Our brain enters a chemically altered state — not unlike a drug high.

Let’s unpack what actually happens inside your brain when Cupid’s arrow lands.

Dopamine: The Pleasure Molecule Takes the Wheel

When you’re falling in love, your brain is flooded with dopamine — the neurotransmitter most commonly associated with pleasure and reward. It’s the same chemical spike you’d get from sugar, gambling, or cocaine.

Studies using brain scans show that when people look at someone they’re romantically in love with, the reward centers of their brain — especially the ventral tegmental area (VTA) — light up intensely. The VTA is packed with dopamine neurons. These are the same circuits activated by addictive substances.

No wonder falling in love feels addictive. You want more of that person. More time. More messages. More touch. The brain, on a very primitive level, starts saying: This feels good — keep it going.

Oxytocin and Vasopressin: The Bonding Agents

Once physical intimacy enters the picture, the brain begins to release oxytocin and vasopressin — two hormones deeply tied to bonding and attachment.

Oxytocin is often called the “cuddle hormone” or “love hormone.” It plays a key role in forming long-term trust and social bonds. It spikes during hugs, kisses, and sex — and it encourages the brain to associate the other person with safety and comfort.

Vasopressin, meanwhile, has been shown to promote monogamous behavior in animals and is tied to long-term attachment. It reinforces commitment and protective instincts.

Together, these chemicals lay the groundwork for turning infatuation into deeper emotional connection.

Serotonin Drops: Why You Can’t Stop Thinking About Them

Interestingly, one of the stranger things that happens in early-stage love is that serotonin levels actually decrease.

Low serotonin is often associated with obsessive thinking — and indeed, people newly in love often report “intrusive thoughts” about the person they’re falling for. They check their phone constantly. Replay past conversations. Worry about being liked back.

A 2005 study even found that people newly in love had serotonin levels similar to people with obsessive-compulsive disorder.

In other words, if you feel just a little bit crazy when you’re falling for someone — that’s not your imagination. That’s your brain on love.

The Prefrontal Cortex Gets Quiet

The prefrontal cortex is the part of the brain responsible for rational thought, judgment, and impulse control. And during the early stages of romantic love — it becomes less active.

That’s why love can make you do things that, in hindsight, seem unwise. Like ignoring red flags. Or taking huge emotional risks.

From an evolutionary standpoint, this “judgment fog” might serve a purpose. Falling in love is a vulnerable act — biologically, emotionally, socially. Suppressing risk-averse thinking may help people leap into relationships without overanalyzing.

But of course, this same fog is why falling in love can feel exhilarating and dangerous at the same time.

Love, Attachment, and the Brain’s Long Game

What’s remarkable is that the “in love” state is only the beginning. As time passes and couples stay together, the chemical cocktail shifts. Dopamine highs stabilize. Oxytocin and vasopressin continue to promote bonding and long-term trust. And the prefrontal cortex comes back online.

If you’re lucky, the thrill of early love gives way to something deeper: attachment. Psychologist John Bowlby’s attachment theory suggests that our adult romantic bonds mimic the patterns we formed with caregivers in early life — secure, anxious, avoidant.

So while love begins with chemistry, it doesn’t end there. Our attachment styles, our past traumas, and our learned patterns of trust all shape what happens next.

So, What Was I Thinking?

The next time you wonder why love made you reckless, euphoric, or wildly irrational — remember, your brain was under the influence. And it wasn’t just metaphorical.

Falling in love is a full-brain, full-body event. It hijacks reward systems. Silences critical thinking. Pushes us into emotional risk. And still — most of us would do it all again.

Because even with all its irrationality, love remains one of the most deeply human things we do.

And neuroscience just might agree.