Of Endorphins and Serotonin

What happens in a relationship and why does passion die off?

It could be because of the brain, the single most important sex organ:


Endorphins is a neurochemical that can be produced at the frequent presence of a loved one.
Endorphins are a group of chemicals produced by the hypothalamus and the pituitary gland in the brain. As they travel through the bloodstream, endorphins act as natural painkillers and create a sense of well-being.

Sense of Euphoria

A product of endorphins, this creates the 'high' that many people experience when they first fall in love.

Obsessive behavior

Love causes serotonin levels in the brain to drop, causing obsessive behavior, researchers at the University of London have found. It also increases production of cortisol, which can cause high blood pressure and loss of sleep.