I can hear it now: “I’m sorry, I don’t love you anymore. It’s not my fault, though. It’s a chemical imbalance in my brain.”

“People often rationalize their inability to have long-term relationships with psychological reasons — you know, they’re inadequate or whatever, or they lack ego,” Professor Carl E. Wood of Melbourne’s Monash University tells me. “But it may just be a problem in their brain chemistry and when they strike the right chemical mix, they are able to bond and form long-term relationships.”

According to Wood, research into the chemicals that control love, lust, and attachment could eventually result in drugs that would make you fall in love and bond with another person. But before you run to your doctor for a prescription, we’re not quite there yet.

Robert T. Francoeur, a professor of human sexuality and author of The International Encyclopedia of Sexuality, says neuroscientists have been studying the chemical makeup of love, lust, and bonding using something called functional magnetic-resonance imaging (FMRI) for years now. “We have some insights, but no complete explanations so far,” Francoeur tells me over the phone from his home in New Jersey.

They do know, for example, why you suddenly become as excited as a schoolgirl, get butterflies in your stomach, and can’t eat or sleep when you first fall in love. “Natural amphetamines are triggered in the brain and do what any natural or synthetic amphetamine does,” Francoeur explains. “They give you that hyped-up feeling.”

So basically, you’re on speed.

If you’re lucky, when your brain eventually comes down, endorphins kick in. “These are the natural opiates, like serotonin,” Francoeur says. “These give us the feelings of relaxation and security that come with long-term love.”

Combine endorphins with oxytocin, otherwise known as the “bonding” or “cuddling” hormone, and ta-da! You’ve got a long-term relationship.

But Francoeur adds that while you can isolate the chemicals involved, it is harder to determine why amphetamine-fuelled lust turns into more relaxed long-term bonding in some cases and not others.

A lot of it, he explains, has to do with our “love map”: “a unique, idiosyncratic sequence of events that determine who and what we are attracted to. Some of this is encoded in the brain before birth. Other things like sexual orientation and gender identity are part of it. Even the image of your first love can contribute to your ideal-lover template.”

Then there are pheromones, chemicals our bodies release into the air to make people go “hubba-hubba.” While scientists are still unclear about how we detect and respond to pheromones, entrepreneurs have made a killing hawking their magic.

Francoeur says that while they have been able to identify pheromones and even chemically reproduce them in a lab, there is no proof that slathering yourself in pheromone cream will attract an endless number of women. “There is no research,” he says. “People claim to have done studies, but I’ve never see them in any journal.”

Of course, when it comes to attraction, most people couldn’t give a rat’s ass about scientific proof. They’ll try anything. Even menstrual soup. In his research, Francoeur has come across examples in African countries, parts of Brazil, and even among African Americans living in the Southern states, of women preparing food with menstrual blood, believed to contain pheromones, to feed to their husbands and boyfriends.

“I just got another confirmation from Haiti of women mixing menstrual blood in soup, hamburgers, or even coffee,” Francoeur says. One of his African American students was all too familiar with the practice: “She said, ‘Oh yeah, that’s “fix’ns,” as in, “You gotta have good fix’ns to keep your man.”’”

Obviously, there is no simple recipe when it comes to attracting and keeping a mate. And though many of us will admit that falling in love has much to do with the chemistry between two people, narrowing long-term love down to a chemical formula is undeniably simplistic.

Still, Wood is confident that one day, research will lead to a pill that produces feelings of lust or love, and that this will be helpful in maintaining happy, healthy relationships. But even he admits that, as with Viagra — which can treat the physical problems associated with erectile dysfunction but can’t solve the psychological problems and conflicts in sexual relationships — a pill may be able to create the physical sensations of love, but it can’t guarantee that it will last.

Of course, that didn’t stop Viagra from becoming the highest-selling prescription drug of all time.