The Brain, particularly the hormones it produces, is also one of the contributing why love and attraction are felt. Almost everyone type cast heart as the solely responsible for love but on top of that, the brain is also playing a very important in terms of all kinds of love.

Your Amazing Brain has revealed the proposed three stages of love by Helen Fisher of Rutgers University including the brain hormones and chemicals that mediate these stages. The stages are specified chronologically as; lust, attraction, and attachment towards one are valentine. 

The first stage of love is lust and mediated by both men and women sex hormones; testosterone and estrogen respectively. Both testosterone and estrogen are responsible for the growth, maintenance, and repair of reproductive tissues. The second stage is defined as an attraction it is also brain-mediated by a substance such as adrenaline, dopamine, and serotonin.

Adrenaline and cortisol are increased when the stress response is activated such as in cases when someone starts to question the feeling of falling in love. The celebration of Valentine's Day may reflect the high concentration of a brain neurotransmitter called dopamine. High blood levels of dopamine enable a person to concentrate more and just on romantic love compared to other things such as food etc.

The third stage is an attachment and is mediated by oxytocin and vasopressin. Oxytocin, according to Web MD, is a hormone released during sex and other intimate activities such as hugging or holding hands. Oxytocin is proven to contribute to strong social bond and relationship between mammals.  Vasopressin also signaled by the brain is very important in a long-term commitment with everyone's valentine because this hormone is released in the bloodstream after making love.

Adrenaline, dopamine, serotonin, oxytocin and vasopressin are not just brain hormones that are released when expressing love and celebrating Valentine's Day but are also important in another aspect of life processes. These hormones are very important in the normal physiologic aspect of a human being. In fact, some of the hormones were synthetically produced in the pharmaceutical market as a medicine in treating some kind of endocrine pathologies.