“All you need is love.”

“Love is a drug.”

“You call it madness, but I call it love.”

woman grinning at man

Because love is so fundamental, the mind and body have unique ways of alerting us of it.

So what’s really behind these overwhelming feelings?

Here’s how your body changes when you’re head over heels.

women affectionately hugging

While attraction raises the levels of some hormones, others, like serotonin, drop.

Low serotonin is also associated with anxiety, depression, and other mood changes.

For example, there’s some truth to the phrase “heart skips a beat.”

woman with upset stomach

Feelingbutterflies in your stomachis another physical sensation you’ll likely notice when you’re smitten.

According to psychiatrist and neuroscientist Dr. Daniel Amen, a fluttery stomach is triggered by your nervous system.

Though this may sound uncomfortable, the good news is that cortisol levels eventually stabilize in long-term relationships.