Throughout history, the mysterious effects of being in love — racing pulse, sweaty palms, butterflies in your stomach, glowing cheeks — have been attributed to the desires of the heart. Love has inspired plays, poetry and art. The Romans tailored mythology to accommodate love, portraying Cupid as the tiny-winged child of Venus — the Roman goddess of love — who shot people with arrows and infected them with love.

After thousands of years believing love was part chance, a little circumstance, and mostly mystery, scientists are now busy discovering not only what parts of the brain are responsible for feelings of sexual chemistry, romantic love, and long-term attraction, but also what chemicals cause the feelings of romantic excitement and contentment.

So is your Valentine’s date your perfect mate? Are they the man or woman of your dreams? Or have you fallen for someone who embodies none of the qualities you look for in the ideal mate, but just feels right? Did Cupid’s arrow really strike?

Possibly­ — if Cupid’s arrows are tipped with the love chemical phenylethylamine. Those of us not looking for answers with wings can look to scientists’ speculation that “true love” is some combination of factors ranging from complementary genes to intoxication from pheromones.

Research shows that people seek out mates with genes that are enough like theirs to be compatible, but different enough to be a good complement and to provide their child with a strong immune system. And pheromones may help you to “sniff” out the right person. These chemical scents released by the body act as a billboard, broadcasting essential information about what you have to offer others.

When you find a person that makes your heart race and your cheeks flush, you’re said to be in the infatuation or attraction phase of love. This is when you can stay up all night talking on the phone, or spend days holed up in a hotel room making love.

You’ve been hit with Cupid’s arrow, the one tipped with phenylethylamine (PEA). PEA really is known as the “love drug,” because it controls the flow of other amphetamine-like chemicals between nerve cells and is responsible for taking you from the initial lust sensation to the attraction phase of being in love. Dopamine is another chemical present in high concentrations in people “in love.” It makes you feel good, and is responsible for that rosy glow people tend to get.

Another chemical, norepinephrine, stimulates the production of adrenalin, which makes you excited and causes your heart to race. This cocktail of love potion chemicals — PEA, dopamine and norepinephrine — is what’s responsible for that euphoric feeling of being in love. Anytime your body simulates the physiological state of romantic love, like when your heart is beating fast and your palms are sweaty after a long run, you’re more likely to associate the next person you meet with feeling in love. So watch out next time you stop for a drink on your run!

Living under the spell of this love potion can be exhausting. And addictive. People create a physical need for this cocktail of love chemicals, so when they start to fade, “love junkies” who crave the first feeling of being in love tend to stray from their partners. This can be anywhere from 6 months to 3 years after getting into a relationship, depending on the person. However, those that stick it out get to move on to the comfortable, reassuring attachment stage of love.

Perhaps Cupid was meant to explain the human phenomena of monogamy as well. Humans are socially monogamous, but scientists tell us that we don’t fall into the 3 percent of monogamous mammals.

From a scientific point of view, males are always ready for a sexual encounter, and any female can be viewed as a possible partner. But an arguably more convincing piece of evidence against the natural state of human monogamy is our chemistry.

On the other hand, prairie voles ­— whose love chemistry is most widely studied — are small, mouse-like animals that according to their sexual behavior, are truly monogamous. Before mating, males and females are friendly with other prairie voles of both sexes. After choosing their life partner and mating once, however, these rodents become fiercely monogamous to a point where the male will defend his mate from any other wandering males that may venture near her.

This all occurs because a chemical called vasopressin is released postcoitus which, along with oxytocin (which humans also secrete), promotes the formation of strong feelings of attachment and partnership. When given a compound to suppress vasopressin, the prairie voles’ fidelity wanes and they lose their desire to defend their mates from the advances of other males.

Though humans don’t secrete vasopressin following a love-making session, there are other powerful chemical and neurological influences at work that make us happier, healthier, less stressed and longer-lived when we live in pairs.

During the attachment phase, when couples bolster their long-term connection, oxytocin and endorphins are released. Oxytocin is affectionately known as the “cuddling chemical,” which plays a role in both sexual arousal and romantic love. It responds to emotional cues, like a sexual thought or fantasy, and physical cues such as looking in the eyes of your lover, hearing their voice, hand-holding, cuddling, touching, sex and orgasm.

Since oxytocin is released during sex and with orgasms, every time a couple makes love they grow more deeply attached and in love with each other. So perhaps if you’re having some relationship problems, a little romp in the sack might be in order to help remind you what that great chemical high feels like. Oops, I mean, why you love your partner so much!

Endorphins, a close cousin of morphine, are plentiful in long-term relationships. They are anxiety-reducing and pain-killing chemicals that induce pleasure, comfort, tranquility and reassurance. Bonds through endorphin release are formed by intimacy, dependability and shared experience, and the longer you are with someone, the more endorphins you release, so the more you love them. This explains why the longer you are with someone the harder it is when you are separated.

These chemicals may not be as exciting as dopamine, norepinephrine and PEA, but they are much more addictive. The draw of being in a long-term, comfortable, monogamous relationship is much stronger, and though you may not get exactly the same high as when you were falling in love, the oxytocin and endorphins give you a more sustainable chemical dependence.

So here’s a little science tidbit to help you out on Valentine’s Day. Chocolate contains PEA, which gives you that same sensation as falling in love. So go ahead: Buy chocolate for Valentine’s Day and get that same excitement and bliss as when you first fell for each other. It’s like a little box of love.