Chemistry of love

Me and my valentine

Happy Valentine’s day, everybody!

Today is the day we celebrate love.

But… what is love from a chemistry point of view?

First of all, love can be divided into three phases:

  1. Lust
  2. Attraction
  3. Attachment

In each phase different hormones play a crucial role.


Lust is strong related with libido. The two hormones involved at this stage are testosterone and estrogen.

Both play a role in men and women. Testosterone increases libido in both genders. Some women report being more sexually motivated around the ovulation day, when estrogen levels are highest.

Adrenaline is produced in stressful or exciting situations. It is typical of the first phase of love, it increases heart rate and gives a sense of intense energy, sleeplessness and loss of focused attention.


This is the “falling in love” phase. The chemical compound mostly involved in this stage is dopamine.

Dopamine seems to be the neurotransmitter involved in mate selection. It is produced by hypothalamus and plays an important role in the brain’s reward center. It gives us a feeling of pleasure and makes us feel energetic and euphoric. Dopamine lowers our appetite and sleep need. That is why when we are in love we can’t eat nor sleep.


In this phase several chemical compounds keep us connected with our valentine.

Oxytocin, which is triggered by dopamine, is the “cuddle hormone”. It is release during touching (and in women during labor and breastfeeding). It is produced by the hypothalamus and favors the sense of attachment and our need to care for another person.

Serotonin, which can increase the dependence toward our beloved one. It is known as the “happiness hormone”. The release of serotonin makes us feel good, so we invest time and effort to keep up this positive feeling and therefore we stay in the relationship.

Endorphins, gives a feeling of calm, relieves pain and reduces stress. It is produced when the “honeymoon phase” is over, more or less after 2 years into the relationship.

Love is a complex and extremely regulated event and all these compounds help us to create and maintain relationships. But, remember, chemistry is not everything. Culture, circumstances, effort and respect are equally important elements for the success of a relationship.

Make Love, Not War.


Yung and Alexander, “The Chemistry Between Us: Love, Sex, and the Science of Attraction”, (2012), Penguin Putnam Inc

Patil, “The Chemistry of Love”, (2014),


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s