Butterflies in your stomach, a racing heartbeat—you probably remember those symptoms well from your first middle school crush. As an adult, they’re actually your body’s subtle clues that you’re falling in love (or lust, at least). At the start of a relationship, a series of truly fascinating chemical reactions occur throughout your nervous system and hormones. From the first time you meet to climbing under the sheets, here’s what’s happening to your body as you fall in love.
Kesha wasn’t too far off when she described love as a drug, according to a 2010 study conducted at Rutgers University. Researchers concluded that falling in love is much like the sensation of feeling addicted to drugs with the release of euphoria, including brain chemicals like dopamine, oxytocin, adrenaline, and vasopressin. Kat Van Kirk, PhD, a clinical sexologist and licensed marriage and family therapist, says these chemicals are released throughout different points of attraction, and help bond you with your partner. Like drugs, the more time you spend with this person, the more addicted you become, she says.
Having a few too many glasses of wine makes you less inhibited, fearful, and anxious, and more aggressive and boastful—and so does oxytocin, the “love hormone,” according to a University of Birmingham study. Researchers pooled existing research into the effects of both oxytocin and alcohol and although they impact different parts of the brain, they have similar outcomes.
Before a big date, you might notice your heart rate tick up and your hands get sweatier. It’s not just a nervous tick that causes your anxiety to rise; it’s actually the stimulation of adrenaline and norepinephrine, says Dr. Kirk. “This can lead to having a physical sensation of craving and the desire to focus your attention on that specific person,” she says.
Your pupils dilate
When you’re attracted to someone—sitting across from you at the bar, on the street, laying in bed together—there is a stimulation in your nervous system’s sympathetic branch, which causes your eyes to dilate, says Dr. Kirk. (Go ahead, you can test it with your partner—it’s fun!)
You may feel a little sick
It’s normal to lose your appetite or feel uneasy when you’ve just started seeing someone new. That’s your body’s way of telling you that you really like that person. “Lovesickness may actually be the stress hormone cortisol contracting the blood vessels in your stomach, making you feel sick,” Dr. Kirk says. This usually fades over time as you become more comfortable with your boyfriend or girlfriend—but could also partially explain why many brides and grooms feel like they can’t eat at their wedding.
Being in love might give you superpowers
Ever heard stories of panicked moms lifting cars off their trapped children? While it might seem insane that the combination of love and fear can give you sudden superhuman strength in an emergency, anecdotal evidence suggests it really can happen. (It’s pretty much impossible to scientifically research this phenomenon, called hysterical strength, because it’s difficult to replicate those conditions for a study.) It’s not just parents who have experienced hysterical strength; people who are in love have, as well. “The oxytocin released in your system when you fall in love can actually increase your tolerance for physical pain,” Dr. Kirk says. Move aside, Prince Charming—love will save the day.
You won’t be able to keep your eyes off your partner
There’s a scientific reason why you have photos of your love set as your smartphone background or framed on your desk. The desire to literally look at your partner’s face comes from the brain’s release of dopamine, says Dr. Kirk. “This is the same effect on the brain as taking cocaine because it stimulates the desire/reward response related to intense pleasure,” she says. In other words, when you scroll through photos from your vacation together, you get a surge of energy, as your desire is being fulfilled.
