So you have a crush.
It’s the start of a chemical rollercoaster inside your brain. Hold tight, because once you start down this track there’s no going back. 3, 2, 1…
1. You get all flustered when you’re around them, your heart beats faster and your hands get all clammy.
Levels of the hormone adrenaline go up when you’re around someone you fancy, leading to a whole host of really attractive reactions from your body.
2. Your thoughts about them border on obsessive.
When you fall in love, levels of the hormone serotonin (which has a calming affect) appear to drop. Serotonin levels also drop in people with Obsessive Compulsive Disorder, which might explain just why you can’t stop thinking about your crush.
3. You think they’re pretty much perfect.
Which might not actually be a bad thing. One study found that people who idealised their parters (and vice versa) were more satisfied in their relationships.
4. Your cortisol levels go up when you’re falling in love.
Also known as hydrocortisone, cortisol is a hormone that is released in reponse to stress. Not exactly surprising, as it can be a very stressful time.
5. In women, testosterone goes up, but in men it goes down.
This kind of evens things out. “It’s as if nature wants to eliminate what can be different in men and women, because it’s more important to survive [and mate] at this stage,” researcher Donatella Marazziti told New Scientist.
6. If you’re lucky, they like you too.
That’s most likely if they have genes that are different to yours, according to one experiment in which women smelled men’s tshirts. They overwhelmingly prefered those tshirts belonging to men with different immune system genes from their own.
7. You can also expect euphoria, sleeplessness, loss of appetite, and a rush of motivation.
You can say thanks to neurotransmitter dopamine for that. Dopamine is also what is responsible for making love feel addictive (among the many, many other things it does).
8. And when you finally kiss? SO MUCH DOPAMINE.
Dopamine spikes during novel experiences and makes us crave more.
9. Kissing also makes your pupils dilate.
Which could be why we close our eyes.
10. Your heart beats faster, too, and more oxygen reaches your brain.
All thanks to neurotransmitters epinephrine and norepinephrine which promote the fight-or-flight response.
11. The hormone oxytocin can also be triggered by kissing.
Often erroneously called the “love hormone” or “moral molecule”, oxytocin can do a lot of things depending on the context. But it is thought to be what helps keep the love in a relationship alive long after the initial honeymoon period is over.
12. Over time, kissing appears to lower your levels of stress hormone cortisol.
The longer the relationship, the greater the decline.
13. Eventually the other hormones that went a little crazy will have returned to normal.
Around a year after falling in love your levels of serotonin should be back to normal, so no more obsessive thinking.