The Chemistry of Love

I've been looking into the brain chemistry behind the emotional response called "love." Love is a very complex biological interaction between any number of different brain chemicals, most notably the following:-

That Initial Spark

Nerve Growth Factor

The first sign of love is triggered by a small protein hormone molecule called nerve growth factor. This neurotrophic hormone is released the moment one first falls in love. Nerve growth factor is known to cause euphoria and feelings of emotional dependency. Its release leads to the release of all that follows - the attraction and lust reactions, infatuation and, in the long term, feelings of bonding and attachment towards one's partner.

Norepinephrine

This hormone stimulates production of adrenalin, which causes the heart to race. Typically released alongside PEA. When someone in love says that their heart "skipped a beat," this would be the cause.

Lovesickness and Infatuation

These hormones are, in a complex manner, responsible for romance, physical and sexual attraction, lust and infatuation.

Phenylethylamine, also known as phenethylamine or PEA

Chocolate is rich in PEA. As a naturally-occurring brain hormone, PEA induces feelings of being head-over-heels in love; the symptoms include loss of concentration and sweaty palms.

Dopamine

The reward hormone, dopamine is also produced by the brain. Dopamine increases feelings of wellbeing and of anticipation - looking forward to something, usually the next encounter with the object of infatuation.

Serotonin

Serotonin is responsible for feelings of infatuation with something or someone. Like the other hormones, serotonin operates on the brain's limbic system, the part of the brain responsible for emotional responses and feelings.

Ghrelin and Peptide YY

Ghrelin is a natural hormone, known as the "hunger hormone." The stomach produces ghrelin, which tells the part of the brain called the hypothalamus that the stomach is full. Likewise, the intestine also produces a hormone called Peptide YY when it is full, telling the hypothalamus to turn off cravings for food.

A person who is deeply in love is often seen to have lost their appetite, for as long as they remain infatuated by the object of their desire. These hormones are the cause of this appetite loss.

Lust

Oestrogen and Testosterone

Practically everyone has heard of these two hormones. Apart from moderating the sexual functions of males and females, these hormones also induce feelings of lust, arousal and attraction; by triggering erections in a man, distending the nipples and clitoris and vaginal secretions in a woman and dilating blood vessels in the skin to cause hot flushes, the body shows its sexual interest in a potential mate.

Attachment

The following two chemicals are strongly linked with bonding and long-term attachment between partners.

Oxytocin

Oxytocin is released in a number of ways - being caressed; being kissed, particularly if the kissing involves nibbling of the lower lip; being in good company; just after an orgasm. A mother and baby release oxytocin throughout the duration of pregnancy and just after childbirth.

Oxytocin promotes emotional bonding and attachment between people, particularly between mothers and children. The so-called "trust hormone," oxytocin opens the mind to trusting the object of attachment. The effects of oxytocin can last for up to two years from exposure.

Vasopressin

Mostly found in males, vasopressin has the same effect as oxytocin, in that it stimulates pair-bonding. Vasopressin could be involved in feelings of fidelity towards one's partner.

It's All Chemistry

Next time someone talks to you about "chemistry" in terms of an ongoing relationship, you can tell them that their words are not just a metaphorical expression.