The Science of Love according to Prof. Sarah Tonin

Written by Sam Lethbridge on Wednesday 14th February 2018

Dr. Samuel Lethbridge, Senior Science Writer at LEC (An OPEN Health company), and Dr. Sarah Tonin explore the scientific processes behind the feeling of love and examine what's really going on with your hormones when cupid's arrow strikes:

“Hello! I’m Professor Sarah Tonin, and I’m going to tell you a little story about the science of love.

There are three key stages to falling in love. The first is lust – which is primarily driven by the sex hormone testosterone. The second stage is attraction – where you begin to focus all of your attention on your partner. The third and final stage is attachment – where your body and mind make a longer lasting bond to your partner

So let’s first take a look at lust…” 

“Androgens such as testosterone are central to sex drive in both men and women. And it’s this sex drive that leads us to go out and look for love in the first place. But testosterone doesn’t act alone in this; a balance of social circumstances and experiences, oestrogen and other bodily systems determine when, where and how often someone feels lust. So what about attraction?”

“Romantic love blossoms as a person starts to view another as special or unique. The lover begins to focus all of their attention on their beloved, intensifying the importance of any desired traits and overlooking any flaws. These feelings are a result of changes in the neurotransmitters dopamine, adrenaline and serotonin.”

“Increased dopamine can cause feelings of ecstasy and intense energy. But the person may also experience mood swings when things aren’t going so well.

Increased adrenaline causes alertness, sleeplessness and loss of appetite.

A decreased level of serotonin causes impulsiveness and obsessive thinking about the partner.

All of these changes cause the sweaty, heart-racing feeling that’s characteristic of romantic love.

Which leads us to attachment…”

“A relationship couldn’t possibly last without attachment. And we wouldn’t achieve this state without the hormones oxytocin and vasopressin. Oxytocin is released by the hypothalamus and acts like the glue that binds the pair together, metaphorically that is! Vasopressin helps maintain this social affiliation and the feeling of togetherness. That feeling of happy togetherness is sometimes called ‘companionate love’ – oh doesn’t it make you feel warm inside?”

So get out there and find love this Valentine’s Day! Happy Valentine’s Day from LEC!

If you'd like to find out more about what LEC do, they'd love to hear from you! Drop MD, Marie Little, a message at Or, if this article has peaked your interest, why not take a look at a slightly different take on Valentine's Day?

Illustrations by Hannah Cox, Digital Designer.