The RSC guide to love and Valentine's

A Chemistry World story on the chemistry of love has resurfaced after two years, as one of the most emailed BBC news stories. 

The heightened interest in the story headlined Sex Chemistry 'lasts two years' is presumably down to the approach of Valentine's Day.

The article explains why lovers' early passions subside when their 'lust molecules' fade; however it is replaced by another molecule which has been linked to a longer-lasting bond. 

Is there more to love and life than chemistry? The RSC explains:

Whether you are looking to tempt a future partner, ward off unwanted Valentine advances or simply get through the day, it all comes down to chemistry.

The romantics of us may want to believe that love really is a mystery of the soul.

The science shows that the mystery is perhaps not so profound. 

Let the RSC explain the real chemistry behind the warm and tender feeling that love is meant to bring. If you don't want your romantic notion to be contaminated with a cocktail of chemicals, then look away now...

The excitement and feeling of love is a cascade of chemical signals speeding rapidly through the brain to trigger electrical or chemical effects. Via nerve cells, these are then involved with controlling what we perceive as emotional reactions. 

We are then unable to control some of the familiar effects such as racing heartbeat, sweaty palms and breathing heavily. 

PEA-Phenylethylamine (or "jubilation")

This fishy-smelling hormone, often found to be low in depressive people, is similar to adrenaline. It is linked to pulse rates, and is significantly higher after physical activity, 
Research shows this may be the trigger for "romantic love", and may lead to sweaty hands, lumps in the throat and butterflies in the stomach.

But after 2-3 years the nerve endings in the brain will have adapted to the increased levels of PEA and the excitation sadly fades. 
This chemical may also explain the high divorce rates which peak close to the forth year of marriage. 

This drug can be found in chocolate and almonds, but unfortunately may be rapidly metabolised before significant quantities can reach the brain.

Oxytocin (the "cuddle" hormone)

Not only can we blame the physical responses of lust and the honeymoon period of love on chemicals. Chemistry is also responsible for the perhaps less tangible desire for tenderness, comfort and physical and mental closeness.

The hormone oxytocin is responsible for these emotional feelings; it has also been associated with maternal behaviour, trust and generosity.

Levels of oxytocin soar with a tender touch, sexual arousal and after orgasm, creating a feeling of safety and comfort and increasing the bond between couples after an amorous encounter. 

The more intimate encounters you have with one partner, the more you associate the pleasant feeling oxytocin brings with that person. This chemical is the long-term glue of relationships. However an overdose of this glue might manifest as an infatuation or obsessive dependence.  

Serotonin ( the 'happiness' chemical), chase away the winter blues by eating chocolate
This chemical mainly affects the brain and about 10 milligrams are needed for psychic stability. Lack of serotonin leads to lack of drive, sleep disorder, anxiety and depression. Serotonin can be provided by foods such as bananas, pineapple, strawberries, raspberries, sesame, rice pudding and chocolate. 

Studies have also shown that levels of serotonin in the brain depend on our exposure to light. So rather than wallowing alone in a dark room this Valentine's, indulge in a massive rice pudding smothered in strawberries and chocolate to get you through.

"Don't wash, Will arrive in Three days" a private message from Napoleon Bonaparte to his wife-

Experiments have shown that attraction between two people is crucially influenced by body odours and pheromones- love will only work if noses agree. Scientists claim we are more likely to be attracted to the smell from someone with a different genetic make-up to our own, and repelled by the odour of someone who is genetically similar. If in doubt whether you want the attention, have a good scrub or douse yourself with garlic! 

Related article

Sex chemistry 'lasts two years'
Scientists find how a hormone change brings about the shift from early passion to long term romance (BBC News 01 February 2006)