If you have ever been in love you probably have fond memories of the butterflies in your stomach, the euphoric happiness and the increased sex drive. Unfortunately, this altered state of being does not last forever; within six months to three years you will be back to your old self. What causes these emotions and the initial attraction? And why does some relationships last far beyond the first rush of feelings?

People like to claim that love comes from the soul or possibly the heart, all depending on how far they wish to push the metaphors. Realistically, it all happens in your brain and it's a chemical reaction.

In the beginning...

You see her from across the room and immediately feel you have to get to know her. Bravely you approach her and soon hours have past without either one of you noticing. What happened?

When two people are attracted to each other adrenaline-like neurochemicals start racing around in their heads, speeding up the flow of information between the nerve cells. Dopamine and norepinephrine are also created, dopamine to feel good and norepinephrine to stimulate the production of adrenaline. This process actually increases the speed blood is pumped around your body, so when you say: “She makes my heart race”, you are not speaking metaphorically. These three chemicals is what create infatuation and make you want to talk all night or have sex for hours.

Forming a relationship

It is your fourth date and you are soon to be a couple. You feel close to her emotionally, physically and romantically. What process in your brain causes you to feel so attached to a person who just recently entered your life?

Once we are in love, another booster is released: Oxytocin. Oxytocin is best known for it's role in mother-child bonding, but it also helps us form romantic relationships. This chemical has both mental and physical triggers, such as the voice of your lover or even a sexual fantasy. It prompts cuddling between partners before, during and after sex. Even better, both men and women become calmer and more sensitive to the feelings of others under the influence of oxytocin.

Happily ever after?

If “I am just not in love with you any more” or “My feelings for you have changed” sound familiar to you, then chances are you have reached phase two of your relationship.

After a period of time, the initial infatuation subsides and many couples choose to break up at this milestone. However, if you stay together a whole new group of chemicals take over. They are created by endorphins: Morphine-like opiates. When we are being constantly reassured by intimacy, dependability and shared experiences these come into play. Naturally it makes our relationship less exciting, but it will be all the more addictive. It's the lack of these chemicals that causes us to miss our loved ones when they are not with us.

Do not despair, though, if your partner is far away or you long to experience a chemical romance of your own; hot chocolate is a good replacement. It's full of that adrenaline-like neurochemical phenylethylamine.