What is Oxytocin?

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Can a nasal spray make someone fall madly in love? Dozens of marketers of oxytocin nose sprays would like buyers to think so, but buyer, beware: This hormone is more complex than it seems.

Oxytocin is a hormone secreted by posterior lobe of the pituitary gland, a pea-sized structure at the base of the brain. It's sometimes known as the "cuddle hormone" because it is released when people snuggle up or bond socially. Even playing with your dog can cause an oxytocin surge, according to a 2009 study published in the journal Hormones and Behavior.

The cuddle hormone has a dark side, however. It can intensify memories of bonding gone bad in cases where men have poor relationships with their mothers. It can also make people less accepting of people they see as outsiders. In other words, whether oxytocin makes you feel all cuddly depends on the environment.

Oxytocin in women

Oxytocin is a particularly important hormone for women, because it is crucial to childbirth and breastfeeding. The hormone causes uterine contractions during labor and helps shrink the uterus after delivery. When an infant suckles at his or her mothers' breast, the stimulation causes a release of oxytocin, which, in turn, orders the body to "let down" milk for the baby to drink.

Oxytocin also promotes mother-child bonding. One 2007 study published in the journal Psychological Science found that the higher a mom's oxytocin levels in the first trimester of pregnancy, the more likely they were to engage in bonding behaviors such as singing to or bathing their babies. [11 Interesting Effects of Oxytocin]

Oxytocin in men

In men, as in women, oxytocin facilitates bonding. Dads who got a boost of oxytocin via a nasal spray played more closely with their 5-month-old babies than dads who didn't get the hormone zap, a 2012 study found.

Another study found that men in relationships given a burst of oxytocin spray stood farther away from an attractive woman than men not given any oxytocin. Single men didn't see any effect from the hormone, suggesting oxytocin may work as a fidelity booster for guys who are already bonded with another woman.

This anti-social effect of a social hormone brings some nuance to the story of oxytocin. In one study, researchers found that Dutch students given a snort of the hormone became more positive about fictional Dutch characters, but were more negative about characters with Arab or German names. The finding suggests that oxytocin's cuddle effects are targeted at whomever a person perceives as an in-group, the researchers reported in January 2011 in the journal PNAS.

In another study, published in PNAS in 2010, men were given a dose of oxytocin and asked to write about their mothers. Those with secure relationships described their moms as more caring after the hormone dose. Those with troubled relationships actually saw their mothers as less caring. The hormone may help with the formation of social memories, according to the study researchers, so a whiff strengthens previous associations, whether good or bad.

Oxytocin sprays and side effects  

Oxytocin nose sprays also have been considered for use in treating autism. The neurological disorder is marked by struggles with social functioning, so a small 2013 study published in the journal PNAS gave a dose to children and teens with autism and asked the participants to identify emotions based on pictures of people's eyes.

The participants weren't any better at identifying the emotions after the oxytocin burst, but the regions of their brains associated with social interaction became more active. The increased processing could mean that a burst of oxytocin might help cement behavioral therapy for kids with the disorder.

Use of oxytocin sprays outside of a medical context is far murkier, however. The sprays sold online without a prescription promise stress relief and social ease, but they are not regulated by the Food and Drug Administration (FDA). That means that nothing is known about their efficacy, side effects or even if they truly contain any oxytocin.

There are no long-term studies on the side effects of the legitimate oxytocin sprays used in hormone research; most studies give people one dose of the hormone only. Pitocin, a synthetic version of oxytocin given intravenously to stimulate labor, has side effects that include nausea, vomiting and stomach pain.

December 24, 2013 12:24am ET