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Love and desire – is there chemistry?

Arousal mixed with longing, tension, unease and then an explosion of joy after the meeting, dreamy looks, wordless conversations…- who hasn’t lived through these emotional swings? Why do people fall in love with each other and what actually is love? About all that, from the chemical perspective, writes habillitated doctor Elżbieta Gumienna-Kontecka, a professor of the University of Wrocław’s Chemistry Department.

What would you think if I said that ‘Love is chemistry’? And mind you, this isn’t really supposed to be a provocation, more of a summation of contemporary interdisciplinary studies performed by chemists, medical experts, brain researchers, neurologists, physicists and biochemists. Together, we gradually manage to uncover human life processes and interpret the basic functions in terms of chemical reactions. By utilizing different approaches and methodologies, they try to present the current scientific knowledge about what makes people fall in love at first sight, up until moments, when emotions transform into a long-lasting relationship. And while we might get an impression that the center of love is in the heart, in reality it is the brain that’s responsible for faster heartbeats and butterflies in the stomach.

Let’s assume for a moment that our brain and its cells are chemical reactors, and love is a cascade of chemical processes and reactions. In that case, which particles and compound groups will play the most important part? This ‘cascade’ is a series of molecular processes, in which information flowing between nerve cells is transported by compounds called neurotransmitters. When we add hormones and neuropeptides that join them later, we can call all of these compounds guardians of emotions. Among them, we should also name phenylethylamine, noradrenaline, dopamine and serotonin as ‘activators’ for emotions connected with love, and oxytocin and vasopressin as hormones of ‘attachment’. These of course aren’t all ingredients of this ‘cocktail’. Its spice levels are brought up by sex hormones like estrogen and testosterone, and notes of relaxation – by endorphins.

Phenylethylamine makes the soul happy and is responsible for starting the so called emotional swing. Commonly referred to as ‘the narcotic of love’, it has a psychoactive effect. Its increased concentration causes a state of euphoria and reveals itself in joy, confidence, excitement or excessive activity. On the other hand, it causes insomnia, eating disorders, lack of concentration or states of anxiety and depression.

Noradrenaline functions as ‘the love substance’, making the heart beat faster and increasing the pressure, or contractility of blood vessels, and thus causing blushing and increased sensitivity to touch when near a loved one. I’ts responsible for remembering the tiniest details about the loved one and moments spent with them.

We can feel the presence of dopamine on an everyday basis, as it is released after we finish a meal, having sex, smoking cigarettes, as well as taking drugs. Its role is the ‘happiness hormone’, stimulating the reward system. When it comes to love, it increases our activity, motivates for action and causes the state of euphoria, results in us looking at our crush uncritically and perceiving their disadvantages as adorable. However, be ware, as too much dopamine can lead to compulsory behaviors and pathological love addiction. We can summarize its effects shortly – from euphoria to despair, with very noticeable withdrawal effects.

When the dopamine levels increase, serotonin levels decrease. Serotonin is a so called happy messenger in our blood. It is responsible for mental balance, and if dropped below a certain level, we can observe bad moods, distraction and lack of concentration, sleep disturbances, anxiety and depression. The person in love becomes disoriented an falls into extreme moods. It has been shown that acute serotonin deficiency (even below 40% of the norm) can cause paradoxical reactions, which been given the name of micro paranoia of lovers.

Among all of these substances the most important are the effects of phenylethylamine, as it controls the rest of the neurotransmitters. However, despite of its effectiveness, most scientists agree in saying that usually after 18 months, up to 3-4 years, nerve endings in the brain adapt to its increased level. The excitement fades and the falling in love phase ends, at least from the neurochemical point of view.

This phase marks the transition from romantic love to the complex happiness of a mature relationship, where emotions extend beyond simple physical attraction. All of that, again, thanks to the chemistry of yet another set of hormones – this time oxytocin and vasopressin. Oxytocin decreases the levels of stress, reduces the blood pressure, acts as a painkiller and helps in achieving the state of relaxation. The level of this hormone increases during sex, being responsible for pleasure. It is also produced during breastfeeding, strengthening the maternal instinct. When in comes to men, vasopressin dominates, the level of which is crucial in the process of bonding, it stimulates relations, faithfulness and the durability of the relationship.

The oxytocin and vasopressin levels are increased through estrogen and testosterone, the female and male sex hormones, which are responsible for desire and the need for love, guiding our emotional life.

Finally, endorphins – our endogenous opiates are responsible for our well-being, carelessness, a state close to euphoria and are a natural anesthetic.

By framing love in such a way, we, the chemists, are absolutely not aiming to degrade the human existence to just ‘pure chemistry’. These examples show that chemistry is not a human invention, but that everything in Nature is based on it. Therefore, when we fall in love, it’s the chemistry that puppeteers the whole operation from behind the scenes. This chemistry of senses rules love, desire and passion and in effects, makes our lives worth living!

Published by: Agata Sałamaj

18 Feb 2021

last modification: 18 Feb 2021