Updated 31 May 2013

The chemistry of love

The source of passionate love isn’t the heart after all - it's the brain.


The source of passionate love isn’t the heart after all – it’s the brain...
BY THE HEALTH24 TEAM for YOU Pulse magazine

First you feel your heart racing. Then you experience the rush as a feeling of euphoria and a sense of excitement overwhelm you.

Soon you’re hooked – another victim of the chemical reaction we call ‘‘love’’.

When we fall head over heels in love it’s very much the head that’s involved. Whenever we’re in love the brain releases various hormones and neurotransmitters which flood the body with a range of sensations.

You feel butterflies in your stomach when a certain someone’s name shows up on your cellphone. You go weak at the knees when your beloved smiles at you.

You’re giddy with happiness just thinking of the evening you’ll spend together. But your body pays a price for these feelings of bliss.

Price to pay
Your palms become sweaty and you can’t seem to get a word out at the most inopportune moments. You lie awake at night for no good reason. You’re not interested in eating.

The powerful brain chemicals have literally made you lovesick. Is your heart beating so furiously you’re sure others can hear it?

You’re not imagining it. The brain chemical noradrenaline increases your heart rate. This fight-or-flight hormone can also make your mouth go dry – which explains why even the most confident people can become tongue-tied around the person they fancy.

And when your beloved leans in for a kiss . . . well, it’s enough to make you swoon. Hardened cynics may scoff but scientists aren’t surprised – they know a surge in the neurotransmitter dopamine can cause wooziness, along with hot flushes and sweaty palms.

Love certainly has some delightful side effects!

Incredible feats
Feel like scaling a mountain to declare your love? You wouldn’t be the first! Lovers through the ages have achieved incredible feats in the name of love. It’s partly due to the combination of dopamine and noradrenaline which leaves you extremely focused and bursting with energy. It’s also the reason you lie awake at night, your thoughts inevitably turning to the object of your affection.

But it’s possible for the novelty of this wonderful thrill to wear off after six to 18 months. You’re no longer quite so excited when the phone rings. You don’t feel the need to see your beloved all the time. And you have your appetite back.

This return to normal behaviour happens when the body builds up a tolerance for the brain chemicals. As is the case with mind-altering drugs your body then needs more and more to bring on that same feeling of love and infatuation.

The cuddling hormone
That’s where oxytocin comes in. Known as the cuddling hormone, it plays a crucial role in binding people together in intimate relationships. Researchers have discovered oxytocin is released during labour and helps mother and child to bond.

This hormone is also released when things start heating up between a couple and helps increase the sensitivity of nerve endings.

It’s the source of the shivers down your spine and the warm, loving glow that washes over you. When the effect of the other neurotransmitters has worn off oxytocin is the glue that keeps a couple together.

If this is where your relationship is at, whispering sweet nothings into your lover’s ear could stir up the feelings of passionate love again. According to researchers hearing your lover’s voice or even just thinking of him or her can trigger the production of oxytocin.

With all these chemicals rushing through your brain it’s understandable you may lose your head. Give in to the emotions – it’s in our nature to fall madly in love.

A passionate kiss releases powerful forces
The moment lovers lock lips it jump-starts a process in the brain that floods the body with hormones.

The first reaction is in the hypothalamus in the brain, which sets a cascade of hormonal triggers in motion.

It then spreads to the pituitary gland, which releases hormones that stimulate other glands such as the thyroid and the adrenal and sexual glands.

At the same time the kiss stimulates the release of neurotransmitters in the brain such as dopamine, endorphins and serotonin. These chemicals act in areas of the brain that keep us coming back for more.

The hormone responsible for feelings of affection and trust is released by the pituitary gland. As a bonus it makes nerve endings all over your body sensitive to your lover’s touch.

Packed with sensory neurons that fire off messages to the brain and body.

The heartbeat accelerates from 60 to 150 beats a minute.

Adrenal glands
Release noradrenaline, a stimulant that makes your heart beat faster.

Sexual organs
Produce sex hormones. In women the ovaries release progesterone and oestrogen, while in men the testes are responsible for testosterone. There are traces of testosterone in a man’s saliva and kissing may be a way to pass this natural aphrodisiac on to the woman.

Secreted by glands in the skin to trigger sensations of attraction and excitement. Since human pheromones have a reach of just a few millimetres an intimate clinch is the only way to pick them up.

[This is an edited version of an article that originally appeared in the Winter 2008 edition of YOU Pulse/Huisgenoot-POLS.]


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Live healthier

Exercise benefits for seniors »

Working out in the concrete jungle Even a little exercise may help prevent dementia Here’s an unexpected way to boost your memory: running

Seniors who exercise recover more quickly from injury or illness

When sedentary older adults got into an exercise routine, it curbed their risk of suffering a disabling injury or illness and helped them recover if anything did happen to them.