What is chemistry in love

There are a lot of chemicals racing around your brain and body when you're falling in love, as well as when you're engaged in a long-term commitment. Over the years, researchers have amassed an impressive array of evidence detailing the roles of various hormones, neurotransmitters, and more that play integral roles in our love-based relationships.

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Romantic chemistry is scientific.
Chemistry is also difficult to predict.
But chemistry’s not the whole story.
Don’t panic if that intense initial attraction wanes over time — it can be recharged.

Two of those hormones, estrogen and testosterone, play a role in our sex drive. These are the two chemicals that drive lust or sexual desire. And while testosterone has historically been thought of as a "male" hormone, it's present in males and females and is responsible for boosting the libido in everyone, regardless of their biological sex.

There are a lot of chemicals racing around your brain and body when you're in love. Researchers are gradually learning more and more about the roles they play both when we are falling in love and when we're in long-term relationships. Of course, estrogen and testosterone play a role in sex drive. Without them, we might never venture into the "real love" arena.

That initial giddy feeling that comes with a new crush or potential love affair is often characterized by a racing heart, flushed skin and sweaty palms. Researchers say this is due to the dopamine, norepinephrine and phenylethylamine released by the body. Dopamine is thought to be the "pleasure chemical," producing a feeling of bliss. Norepinephrine is similar to adrenaline and produces the racing heart and excitement.

According to Helen Fisher, a well-known love researcher and an anthropologist at Rutgers University, together these two chemicals produce elation, intense energy, sleeplessness, craving, loss of appetite and focused attention. She also says, "The human body releases the cocktail of love rapture only when certain conditions are met and ... men more readily produce it than women, because of their more visual nature."

In 2013, Fisher presented research at the Being Human conference that indicated that several brain chemicals, including dopamine and testosterone, play a role in a person's drive toward romance, sex and other rewards. She suggested that the precise balance of these chemicals could shape a person's personality and influence the type of people they're attracted to. While people with "active" dopamine systems tended to be reward-driven and impulsive, curious, energetic and mentally flexible. These people appeared to be attracted to people similar to themselves. People with more active serotonin systems tended to be conscientious rule followers who also leaned toward similar-minded partners.

But two groups of people seemed to be drawn to their opposites: highly analytical and competitive testosterone-dominant people who were often attracted to the "high-estrogen and oxytocin" types who tended to be nurturing, empathic and introspective. And the attraction went both ways.

Researchers have also used are using functional magnetic resonance imaging (fMRI) to watch people's brains when they look at a photograph of their object of affection. According to Fisher, what they see in those scans during that "crazed, can't-think-of-anything-but stage of romance" — the attraction stage — is the biological drive to focus on one person. The scans showed increased blood flow in areas of the brain with high concentrations of receptors for dopamine — associated with states of euphoria, craving and addiction. High levels of dopamine are also associated with norepinephrine, which heightens attention, short-term memory, hyperactivity, sleeplessness and goal-oriented behavior. In other words, couples in this stage of love focus intently on the relationship and often on little else.

Another possible explanation for the intense focus and idealizing view that occurs in the attraction stage comes from researchers at University College London. They discovered that people in love have lower levels of serotonin and also that neural circuits associated with the way we assess others are suppressed. These lower serotonin levels are the same as those found in people with obsessive-compulsive disorders, possibly explaining why those in love "obsess" about their partner.

Someone walks into a room, and you immediately react. Your palms sweat, your heartbeat quickens, you blush and maybe you stammer or tremble. Then, once they’ve left your sight, you can’t get them out of your mind. It’s as if they’ve cast a spell on you.

“Everything about them feels right, the way they look, smell and taste,” says Robert Navarra, PsyD, LMFT, MAC, Certified Gottman Therapist and Master Trainer. If this intense attraction is mutual, time seems to stand still when you’re with this other person. But why? What is the chemistry of love, and why do we feel it with some people and not others?

Romantic chemistry is scientific.

Although the word "chemistry," referring to a romantic and sexual spark, is not an official, scientific term, the phenomenon is indeed backed by science. Here’s some proof: Helen Fisher, Ph.D., senior research fellow at the Kinsey Institute and author of Anatomy of Love, looked at MRI results of 17 subjects who were intensely in love. When the subjects looked at photographs of their loved ones, the resulting MRI scans showed the areas of their brains associated with reward and motivation and rich in the chemical dopamine were activated. So, Dr. Fisher explains, “When people say they have chemistry with someone, they’re being accurate.”

Chemistry is also difficult to predict.

If only there were a way to predict who we’ll have chemistry with — dating would be so much easier. Unfortunately, explains Justin Lehmiller, Ph.D., research fellow at the Kinsey Institute and author of Tell Me What You Want, most of us can’t foresee what we’ll find bewitching. In fact, speed-dating studies have found that people often don’t pick people with the traits they'd put on their wish lists, he says.

Although a mystery, Dr. Fisher has discovered a science-backed way to at least partially understand why we have chemistry with some people rather than others. From her studies of the brain, she has found four basic styles of thinking and behaving linked with four different brain systems: the dopamine, serotonin, estrogen and testosterone. “Each system is associated biologically with a constellation of personality traits,” she says.

Based on data from her study of 40,000 singles — research for her book, Why Him? Why Her? — she found that men and women dominant in dopamine traits (including novelty- and risk-seeking, curiosity, creativity and energy) are attracted to people like themselves. The same is true for the serotonin-dominant, who tend to be cautious, traditional, rule-following and respectful of authority. “In these cases, similarity attracts,” Dr. Fisher says.

Meanwhile, those who are high in testosterone tend to be analytical, logical, direct, decisive, tough-minded and skeptical — and more drawn to those who are dominant in the traits linked with estrogen, their opposites. Estrogen-dominant men and women tend to be imaginative, empathetic, trusting and emotionally expressive, as well as drawn to those high in testosterone, also their opposites. That said, Dr. Fisher points out that we all have traits in all four systems. “Only when you see the full combination of traits in both partners can you begin to predict their compatibility,” she says. (To see where you land, take Dr. Fisher’s free personality quiz on her website.)

But chemistry’s not the whole story.

Chemistry tends to be a launching pad for relationships, says Carrie Cole, M.Ed., L.P.C., research director and Gottman Master Trainer at The Gottman Institute. “Chemistry opens the door, but it’s what we do with it afterwards that determines whether the relationship will have any legs,” she says.

For relationships to progress beyond the initial intense attraction, trust and commitment must follow. “Trust is knowing your partner is there for you and is someone you can count on,” Dr. Navarra explains. “Commitment is knowing there is no one else you would rather be with, and vice versa. Relationships typically start with chemistry, but need more to work.”

Although chemistry can lead to successful relationships, it should be taken with a grain of salt, Dr. Lehmiller notes. After all, “chemistry and compatibility are two different things, and sometimes the people we feel an overwhelming attraction to are not right for us long-term," she says. "People can get into trouble by rushing to commit to someone when they prioritize chemistry over shared interests and values.” Instead, he says, people should try to strike the right balance between chemistry and compatibility when looking for a long-term partner.

Don’t panic if that intense initial attraction wanes over time — it can be recharged.

“Chemistry with a long-term partner can fade,” Dr. Lehmiller says. “If it does, that doesn’t mean there’s a problem with your relationship.” There’s also no need to panic if you experience chemistry with someone outside of your relationship, Dr. Fisher says. You can simultaneously be deeply attached to your partner, madly in love with someone else and sexually attracted to others, she explains. That’s because companionate love (for a long-term partner), romantic love and lust are orchestrated by three different brain systems, which operate in tandem.

Instead of panicking about a decline in chemistry, reinvest in your relationship by trying to rebuild that spark, Dr. Lehmiller says. To do so, focus on how you and your partner first met and what brought you together and try to relive those initial moments. “When couples tell me how they first met, they light up and turn towards each other,” Cole says.

Then, carve out regular rituals that encourage your connection, whether they’re weekly date nights or five-minute chats each evening to review your days, Dr. Navarra says. In fact, Dr. Lehmiller suggests spending some of this time asking each other deep questions, as with Dr. Arthur Aron’s 36 questions that lead to love, as published in The New York Times. Getting to know each other better on a deep level can actually help build chemistry. “The more couples turn toward one another, the more they’ll want to turn towards each other,” Cole says.

Finally, since novelty boosts arousal, it’s a good idea to be adventurous with your partner; you’ll likely transfer some of the excitement from new experiences onto them. So, plan a date during which you learn a skill (like rock-climbing or painting), try a cuisine that’s unfamiliar to you or explore a new neighborhood. The surge of dopamine you’ll likely experience might be just the ticket to add a spark to your long-term relationship.