The knees get weak, butterflies kick up in the stomach, the heart flutters. Ah, love – in its early stages, that is.

Because once you get about a year into a relationship, the physical manifestations of being in love may begin to fade, according to a study released Monday by the University of Pavia in northern Italy.

The Italians found that a chemical in the brain is responsible for those early relationship feelings, but the levels of the chemical – a protein, actually – recede over time.

The study compared the protein levels of 58 people who were in a new romance to the same number of people who were in long-term relationships, and also single people.

The levels of a protein called nerve growth factor, which causes those weak knees, butterflies and fluttery hearts, were higher in those in a new relationship. And of the 39 people in the same relationship after one year, the levels had dropped to normal.

Actually, the researchers termed it the end of romantic love.

No more romantic love? Sounds depressing.

But there’s hope. Just because a couple doesn’t get the sweats every time they’re together doesn’t mean they’re no longer in love with each other, the scientists cautioned. Rather, the love is no longer acute, as they put it, but is more stable.

What made me lose my butterflies was the source of the study. I mean, these are Italian men – the same shameless flirts who will wink at you on the street and innocently follow you around a piazza. Really, how can they treat love so coldly and analytically?

I’m no scientist, but I know what I see – and based on what I see anecdotally, the verity of the study’s findings seems like a mixed bag.

I’ve always liked to watch couples’ interactions – you know, those romantic hugs at an airport, or how people behave when doing everyday activities like shopping – so the Italians’ findings made me think about the facial expressions I see from my female friends when their significant others walk into a room.

One friend who has been married for more than two years lights up like a Fourth of July sparkler when she sees her husband. Another acts like her boyfriend doesn’t exist – and they’ve been together for less than a year. Another has been married for more than five years, and she never seems to notice when her husband is around.

Then there are my parents, who have been married for almost 38 years and have never been more romantic than they are now. Holding hands, smiling when they see each other, exchanging a spontaneous peck – maybe there’s a chance those NGFs can come back, after all.

Jessica Bloch can be reached at jbloch@bangordailynews.net.