The science of love

Love makes the world go round. It brings us together in times of hardship, it makes colors seem brighter, food taste better and, to be honest, without it what is the point in any of it. But there is no mystical powers involved as Queen may lead you to believe in their song It’s a kind of Magic. It is just a chemical reaction. In fact the BBC say, and I quote:”Events occurring in the brain when we are in love have similarities with mental illness“. I like that comparison. (Careful looking at sources around the web on this subject as a lot of them are incorrect (eg. wikipedia). I’ve taken scientific journals and reliable sources such as how stuff works).


First there’s lust. I won’t go into this in too much detail as I talk about it in an earlier post . This, needless to say, is driven by sex hormones testosterone and oestrogen. We can also transfer these hormones to each other when kissing.

Then there’s stage 2. We’ve all had someone that we just can’t seem to stop thinking about. This is the stage that is said to drive you temporarily insane, where you might start acting like Tom Cruise on Oprah. This is down to a few chemicals. Firstly there’s norepinephrine, which is very similar to adrenaline, the hormone that is associated with “fight or flight”. When you bump into your beloved it starts your stress response off which is why you may go red faced and sweaty.

Then your serotonin is dampened. Serotonin is a neurotransmitter (ie. a chemical messenger in the brain that affects your mood) and is associated with calmness. Lower levels of this are thought to be the reason behind why you can’t stop thinking about that person. Research at University College London showed this to be a similar brain condition as people with obsessive compulsive disorder.

In the longer run there are chemicals that keep us together. Oxytocin is a hormone released during orgasm of men and women and is thought to be associated with trust. It is also thought to be involved with a mother’s attachment to their baby. Weirdly a hormone involved in kidney function called vasopressin is also involved in long term attachment.  Prairie voles, which are normally monogamous, were injected with a chemical that suppressed vasopressin. This caused greatly increased rates of infidelity.

The most important chemical of all however is dopamine. Dopamine, like serotonin, is a neurotransmitter that is associated with addiction. This is what gives us the thrill of seeing that person and it has been shown to last in long term marriages as well as at the early stages.

There are many reasons why it is thought that love has developed in humans (and other animals such as prairie voles). It may be because it leads to better parental care. It may have developed as promiscuity led to increased STI transmission. 

Sorry if this shatters any illusions for you desperate romantics out there. In a way putting such a fundamental force into discrete categories is rather depressing. But hey! that’s what us scientists do.

Is it depressing to think of love as a chemical reaction? Do you relate to the above stages I have described? Please comment below!



10 responses to “The science of love

  1. Yes it is, pretty much! Even our nerve impulses are driven by sodium and potassium moving in and out of our neurons. We are just walking bags of chemicals that for some reason seem to be conscious!

  2. I really like this post. I always feel like I’m going mad when I fall for a girl. Now I know why!!

  3. Haha cheers man. Glad you enjoyed it. Check out some of my other posts in the human behaviour category

  4. Nice blog Ran! I guess breaking it all down to chemicals could take away some ‘magic’ but as falling for people is hardly black and white feel there is still plenty to wonder about! Like why are we attracted to specific people when there are loads of other attractive/funny/ smart people who don’t float our boat ?! Heard we are more attracted to people with ‘opposite’ immune system to our own (don’t know if this is true). Hmmmm, time to sleep – anyway keep posting !

  5. The thing about dopamine is interesting. Parkinson’s disease is characterised by the loss of dopaminergic neurons. Could this mean people with the disease are less likely to stay in long-term relationships?!

    • That’s a really interesting point Joanna. I’ve never thought about that. There is evidence that people on antidepressants find it harder to fall in love but this is more to do with serotonin levels rather than dopamine. I’ve never heard of that but maybe that’s something to look into!

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