Tuesday, February 14, 2017

The Complexities of “The Love Hormone”

New York street art. Photo in
Wikimedia Commons posted by Pedroalmovar.
Oxytocin, commonly known as “the love hormone”, is a small chemical that is produced in the brain of mammals, but can both act as a neurotransmitter and enter the blood stream and act as a hormone. It has long been heralded for its role in both maternal and romantic love, but more recent research is showing us just how complicated the physiology of love can be.

Oxytocin is released in mammalian mothers after birth. It promotes nursing and bonding between a mother and her young. As children grow, oxytocin is involved in how both mothers and fathers “baby-talk” and mirror their children. It is involved in pro-social behaviors in both young and adults: trust, generosity, cooperation, hugging, and empathy. And of course, oxytocin promotes positive communication and pair bonding in romantic couples. Countless studies have found these relationships between affiliation and oxytocin in many mammalian species, giving oxytocin its commonly used nickname “the love hormone”.

But more recent studies show that it’s not so simple.

In a number of recent studies, people have been given oxytocin nasal sprays and tested for various behavioral effects in different contexts… and the context really seems to matter. Oxytocin increases trust, generosity, cooperation, and empathy towards people we already know and like. But it decreases trust, generosity, cooperation, and empathy towards strangers. When we play games with strangers, oxytocin makes us more jealous when we lose and it makes us gloat more when we win. It also seems to enhance many attributes relating to ethnocentrism: It increases our ability to read facially-expressed emotions in people of our own race while making it harder to read facial expressions of people of a different race. When forced to choose between being nice to a stranger of our own race versus a stranger of another race, oxytocin makes us more likely to choose the person of our own race. In studies of both people and rodents, oxytocin decreases aggression towards our families and friends, but increases aggression towards strangers.

Oxytocin is not the universal love hormone we once understood it to be. It helps us direct our positive support towards our “in-groups” (our family and friends) and defend them from our “out-groups” (individuals we don’t know). It is a delicate balance: Too little of it can cause social impairment and make it difficult to connect with loved-ones; Too much of it can increase our anxiety towards strangers and racist tendencies. And to make things more complicated, each of us has a slightly different oxytocin system: sex, gender, social history, history of childhood trauma or neglect, psychiatric illnesses and genetic variations all have profound effects on the oxytocin system.

There is much we don’t know about the role of oxytocin and love. But they are a good fit, because both, it seems, are complicated.

Want to know more? Check these out:

Shamay-Tsoory SG, & Abu-Akel A (2016). The Social Salience Hypothesis of Oxytocin. Biological psychiatry, 79 (3), 194-202 PMID: 26321019

Zik JB, & Roberts DL (2015). The many faces of oxytocin: implications for psychiatry. Psychiatry research, 226 (1), 31-7 PMID: 25619431


  1. Sarah thanks alot for this post.. I am now convinced about the power of oxytocin..Thanks a lot for this nice post.


  2. I agree that the nickname for oxytocin is misleading. It does have love promoting characteristics such as promoting maternal behavior, pair bonding, and increasing trust toward your in-group members. It also helps people recognize facial expressions of emotion. However, oxytocin also does the opposite of promoting love. People who already have a general mistrust toward others will become even more distrustful. Oxytocin increases people’s attention to possible dangers, so it will increase anger and distress toward strangers. This post is on the right track in educating people about all of the contributions oxytocin makes to our lives not just the well-known “love” ones.

  3. This is an informative article, as much of the research focuses on the positive and warm effects of oxytocin. Its role between mothers and infants is crucial during breastfeeding. Additionally, in human sexuality, oxytocin is regarded as the cuddle hormone. Its role in bonding and intimacy during and after sexual activity is highly established. This hormone is typically released after orgasm, which is why most (unless climax was faked, obviously) feel a sense of relaxation and emotionally closeness after orgasm. However, it's worth pointing out that oxytocin has influences in almost all of our relationships - familial, romantic, companionate, and even foes or strangers. It appears as though the hormone might have evolutionarily divisive properties: strengthening bonds with trusted allies and further repelling potentially threatening or untrustworthy strangers.

  4. This article is very enlightening. It also showcases that the characterizing Oxytocin as the love hormone is not accurate. Although it is certainly imperative as a bonding agent with people who are known to us such as children, lover, partner, friends, and family and be a pro-social hormone. It can also reinforce negative behavior or thoughts. It will decreases trust, generosity, cooperation, and empathy which can be viewed negatively. However, I wonder what causes the drastic change, is it the receptor that the hormone binds to or if there is another hormone that is released with the Oxytocin creating that negative response.

  5. Alisha Ludwig, Physio-HardenMay 5, 2017 at 1:36 PM

    This article makes a valid point about the assumption that Oxytocin is a love hormone. Even in my college courses it is referred to as the "cuddle" chemical. In arousal and attraction, Oxytocin is not the only chemical present. Dopamine and GABA, along with serotonin make an impact. Oxytocin is also not a physical chemical, it also emphasizes emotional attraction along with physical