For this Valentine’s Day, why not give your loved one a little dopamine or norepinephrine?

Doesn’t sound romantic enough? Despite the not-so-sexy name, these two chemicals are largely responsible for creating that loving feeling.

Tamra Paolillo, clinic coordinator at Heartland Counseling Services, says being “in love” is all about chemistry.

“When you fall in love, specific areas of the brain experience increased blood flow,” Ms. Paolillo says. “The chemicals that race around in our brain are many, but of particular interest are dopamine, norepinephrine, adrenaline and phenylethylamine.”

These chemicals are connected with different “love systems,” according to the research of Dr. Helen Fisher, chief scientific adviser with Chemistry.com. Dr. Fisher studies the three different systems and the associated chemicals by putting lovers through brain scans.

Dr. Fisher calls the first the “sex drive system.” This system is associated primarily with testosterone. The second system is called the “romantic or obsessive love system.” People experiencing infatuation often have high levels of dopamine and norpinephrine in their brains. These chemicals are natural stimulants and create what Dr. Fisher calls “sweaty palm syndrome.”

“It’s that intense romantic love,” she says. “It’s when you’ve got a pounding heart, sweating palms, you can’t wait for them to call. Love poetry in every culture describes that feeling.”

Ms. Paolillo says the chemical reaction associated with romantic love has both its advantages and disadvantages.

“Increasing levels generally produce exhilaration, excessive energy, sleeplessness and loss of appetite,” she says. “Lovers focus on each other often to the exclusion of noticing negative traits which can lead to problems once the ‘honeymoon’ is over.”

The third chemical system Dr. Fisher outlines in her research is the “attachment system.” She says science connects this system with vasopressin and oxytocin. These chemicals help create the sense of peace and security associated with long-term partnership.

According to Dr. Fisher, the results of her studies do answer a few of those typical Valentine’s Day questions: for example, do you believe in love at first sight?

In a chemical sense, Dr. Fisher says, there is no denying it.

“Love at first sight absolutely exists,” she says. “For some, that romantic love might happen instantly, or, for others, very slowly.”

When it comes to meeting that special someone, Ms. Paolillo says studies have revealed that people have a template for their ideal partner buried somewhere in their subconscious.

“It is this template that determines who catches our eye,” she says. “We tend to look for someone who reminds us of ourselves, and we tend to look for members of the opposite sex who remind us of our parents.”

And what about long-term love? Can couples still have that “madly in love” feeling after several years?

Dr. Fisher says absolutely. But it will likely come and go.

The systems she describes interrelate daily. At times, the attachment system may be the dominant system; at others times the sex drive system may thrust the couple back into an infatuated state.

“But you can feel that rush again,” Dr. Fisher says.

Ms. Paolillo says finding something in common can make all the difference.

“Something that is their ‘glue,’ and either lasts throughout the relationship or they have enough in common that they can find a common interest,” she says.

Despite the exhilaration feeling associated with romantic love, research reports that people do better in long-term relationships. Studies show those in long-term relationships have lower stress levels and a greater overall satisfaction with life.

Lifestyles reporter Betsy Lee can be reached at betsylee@npgco.com.