Love is in the air! Or is that oxytocin?

Have you noticed the chocolates wrapped in bright red paper, teddy bears holding pink hearts in all the stores, and the endless supply of diamond commercials on television? Indeed, this Thursday is Valentine’s Day, which means couples will dote on each other with complete infatuation all day. But what happens after that lovely night out, when the alcohol is gone and the sugar high wears off? Will she notice the hot guys at the beach, and will his eyes wander to the attractive women walking across the street?

Worried? Angry? Crushed? Well, fear not! A dashing group of knights from the University of Bonn galloped to deliver this important news in the November 2012 issue of The Journal of Neuroscience, which featured their findings that hormones can lead to long-lasting effects in love, trust, and commitment.

Boost your “Love Hormones”

Oxytocin is one of the key ingredients for a loving and faithful relationship. This hormone is produced in the hypothalamus, which is located just above the brain stem. In humans and other animals, oxytocin is known to promote bonds between parents and children and between couples. In addition, studies have shown that oxytocin increases trust between people, thus dubbing it the “trust hormone.” However, scientists had not determined if oxytocin could promote long-term monogamous human relationships, until now!

The hypothalamus (red) is located below the thalamus, just above the brain stem.

In the current study, researchers wanted to see how healthy heterosexual males responded to oxytocin. The volunteers in this study were all men, who were either in a committed relationship or were single. They were given a nasal spray of either oxytocin or placebo, and after 45 minutes, they were introduced to a highly attractive woman. (Yes, the men participating in the study later described her as very attractive!) As she moved toward or away from the volunteers, the men then were asked to indicate when she was at an “ideal distance” or one that made him “slightly uncomfortable.”

© Copyright 2012 CorbisCorporation

Because oxytocin increases trust in people, it was expected that the men who received oxytocin would allow the woman to get closer to them. Surprisingly, they found the exact opposite! In addition, the men in committed relationships who were given oxytocin kept a greater distance from the woman compared to the men given a placebo. In contrast, oxytocin had no effect on single men.

Even more striking is that a similar effect was found when the men were shown photographs of attractive women! The men who received oxytocin preferred to keep a long distance from the pictures, whereas the men who did not receive oxytocin had no inhibitions. Thus, oxytocin can prevent men from getting too friendly with women (even attractive ones!), whether they are real or not. Taken together, this study shows that oxytocin can promote long-term monogamous human relationships!

So for this Valentine’s Day, why not skip the champagne and chocolates and just give him a dose of oxytocin? I’d recommend wrapping it in bright red paper nuzzled with a white teddy bears!



Scheele D., Striepens N., Gunturkun O., Deutschlander S., Maier W., Kendrick K.M. & Hurlemann R. (2012). Oxytocin Modulates Social Distance between Males and Females, Journal of Neuroscience, 32(46) 16074-16079. DOI: 

Images adapted from Image Source/Corbis, Wikimedia Commons, and Odilon Dimier/PhotoAlto/Corbis.

Jooyeun Lee

Jooyeun (JL) dreamt about being an artist and yet she is now in her fifth year as a Neuroscience Ph.D. student at USC. As she studied art in college, it opened up a whole new world beyond her perspective and turned out earning a Bachelor’s degree in Biology. Thereafter, she joined a neuroscience lab at California State University, Northridge, studying wound healing response in diabetic neuropathy as her Master’s thesis project. Currently, she studies neurological disorders, such as Down syndrome and Alzheimer’s disease, using Drosophila as a model system.