Falling in love is one of the most important and mentally challenging things that can happen to us, yet we know very little about what it can do to our bodies.
A recent study from the University of California indicates being lovesick is actually a legitimate physical condition.
The team took blood samples from 47 young US women as they began new relationships over the course of two years, and watched for genetic changes in those who fell in love.
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They found that doing so not only impacted women psychologically, but physically - a reaction comparable to coming down with the flu.
Christchurch woman Courtney Vincent is certainly feeling the pain of being loved up.
"The butterflies, everyone has had that feeling, and it intensifies and you feel like you're physically in pain, but it's good so it's quite strange," says Ms Vincent.
"I can't physically deal with how much I'm in love with this person. How is this possible? This probably isn't normal."
Auckland University Medical Science Associate Professor Roger Booth says there is an explanation.
"When you fall in love, you're maybe going to get exposed to different infectious agents that you haven't met before like viruses, so you turn up aspects of the immune system that will help deal with that."
Kiwi psychologist Sara Chatwin says falling in love often leads to stress and anxiety.
"It's a degree of anxiety of not knowing what is going to happen next. So for some people they see that and equate that to feeling a little bit off or a little bit lovesick."
While fewer than 50 women were involved in the California research, Professor Booth deems it a credible study.
"The other things they found were interesting: there wasn't any change in genes associated with stress or loneliness, and the women didn't report being less lonely when they fell in love."
Scientists have suggested it could be to prepare their bodies for impregnation, leading them to believe men's genetic response to falling in love may differ.
Researchers plan to study men next to get a better idea if both genders really do find it painful to fall in love.
For now, it's a deeper insight into the female body's reaction on the road to love.