The hormonal cocktail of falling in love


It’s that time of year again where every social media site is adorned with new lovers settling together, getting engaged or deciding it’s time to start a family. I thought I’d take a look at what makes us as humans fall in love and how exactly it all works.

Firstly there comes lust. Our primal instinct is to search for a mate, which throughout evolution has turned into monogamous relationships and the search for a shared bond. As many of you are probably aware males predominant sex hormone is testosterone. Not only is it responsible for the development of the male reproductive system and secondary sex characterises that arise during puberty, but it also promotes a mans seductiveness and desire for a sexual partner. On the flip side is oestrogen. Which again is responsible for development of the female reproductive system and secondary sex characteristics such as breast development and hip widening. But it also causes us women to search for a physical closeness in a mate.

Next up attraction. Also known as not being able to think about anything but that dreamy boys face. Many neurotransmitters are released in high levels during this period, all eliciting a range of responses. To begin, serotonin which is linked to sexual desire and sexual function actually shows decreased levels. This is a similar occurrence to those known to have obsessive compulsive disorder, which is why as much as you try… you just can’t seem to shift how great that person looked today and you just have to tell everyone you know about them.  Dopamine is responsible for those feelings of desire, need for attention and addiction – the same increase in dopamine levels is shown in those using cocaine. Finally there’s Adrenaline which you make elicit with the ‘fight or flight’ response humans show. It’s associated with the stress response we experience, causing us to feel butterflies in our stomach due to increased feelings of nervousness. Adrenaline also causes our energy levels to surge and our hearts to beat faster, which can probably be used to explain the annoying clumsiness we somehow all suddenly accustom when meeting someone attractive.

Finally the attachment phase. Oxytocin leads to the deep bond that we share with many of our loved ones not only sexual partners. It’s released by men and women during intimate moments such as orgasms, kissing and cuddling. High levels of oxytocin are also present in childbirth and breast feeding, leading to the close mother-infant bond. Vasopressin another hormone you may be familiar with for its function elsewhere in the body such as the kidneys, has been proven to be released after sex and again encourage the bond formed between partners. Both of these hormones are responsible for arguments such as ‘the more sex a couple has the happier they’ll be long term’. Several experiments have been carried out to show the roles of these attachment hormones. Firstly, vasopressin release was supressed in male prairie voles. As a result the males no longer willingly prevented their females from finding another mate as the bond they once shared had weakened. In regards to oxytocin, a twin study was carried out in Sweden that showed differing oxytocin receptors were associated with an increased amount of relationship failings such as a marital crisis and a  difficulty to maintain a long term relationship. Research has also shown that increased levels of oxytocin can be linked to increased empathy in a relationship.


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Lorna Milne

19 year old, Biomedical Science undergraduate at the University of Sheffield.