The Hype About the Love Drug Is Dangerous

Health and medicine explained.
July 17 2012 1:17 PM

One Molecule for Love, Morality, and Prosperity?

Why the hype about oxytocin is dumb and dangerous.

Couple embracing.
Is oxytocin really a "hug hormone"? It's a bit more complicated than that.

Photograph by Thinkstock.

Imagine a molecule that underlies the virtues that glue societies together. Imagine that it brought out the better angels of our nature with just a sniff and could “rebond our troubled world.” Imagine that it was the “source of love and prosperity” and explained “what makes us good and evil.”

Well, carry on imagining. This is a story about oxytocin, and oxytocin is not that molecule.

You could be forgiven for thinking otherwise. For almost a decade, this simple hormone has been relentlessly hyped as a one-ingredient recipe for a utopian society. This molecular high-five, which is released when we hug, tweet, dance, and orgasm, has been linked to trust, cooperation, empathy and a laundry list of other virtues. Io9 anointed oxytocin “the most amazing molecule in the world.” Other writers have added alliteration to breathlessness and billed oxytocin as the “cuddle chemical,” “hug hormone,” and “moral molecule.”

That last one adorns the cover of a new book by Paul Zak, the self-described “Dr. Love” who hugs everyone he encounters. He was recently profiled by Oliver Burkeman in the Guardian, the latest episode in a long flirtation with the media in which he regularly expounds on oxytocin’s supposed wonders. You can see why journalists love him. He’s charming, handsome, and infused with that “big ideas” aesthetic that TED so adores. When he delivered his own TED talk in July 2011, he unabashedly claimed that he had found the molecule behind why we’re moral.


The problem with the moral molecule idea is that it turns science—messy, complex, frustrating as it is—into a tidy fable. It’s a bit too ... well ... TED-dy. It not only tells people what they want to hear but also makes them feel delightfully subversive for understanding the secret simplicity of the world. One molecule underlies morality? Seems far-fetched, but not impossible. Hugs can change the world? Everyone likes hugs! We can counter our imps of the perverse by breathing in the right molecule? Yahtzee!

But these bold words are not backed by equally bold evidence. Oxytocin hype might be storming the heavens, but oxytocin science is still finding its footing. Early studies certainly bathed the hormone in a shiny glow, but later ones uncovered a darker side. The “love hormone” fosters trust and generosity in some situations but envy and bias in others, and it can produce opposite effects in different people. A more nuanced view of oxytocin is coming to light—one that’s inconsistent with the simplistic “moral molecule” moniker.

Oxytocin is made in a part of the brain called the hypothalamus, but it influences the entire body. It spikes when we’re sexually aroused, makes wombs contract before birth, and triggers the release of breast milk. For decades, animal studies have shown that oxytocin is important for social interactions. If you block the hormone, monogamous voles become more promiscuous and ewes neglect their newborn lambs.

Then, in 2005, Michael Kosfeld and Markus Heinrichs asked volunteers to play a game of trust after sniffing either oxytocin or a placebo. (Zak, often solely credited for this work, was the third author on the paper.) The volunteers had to decide how much money to invest in an anonymous partner, who could reimburse them later or keep all the money. Despite the potential for betrayal, the oxytocin-sniffers entrusted more money to their partners than those who sniffed a placebo.

Heinrichs downplays the hype around a “good hormone,” but his study kicked off an oxytocin fever. Various research groups showed that oxytocin sniffs can make people more trusting, generous, cooperative, sensitive to the emotions of others, constructive in their communications, and charitable in their judgments of others. Zak continued to link oxytocin with trust and generosity, although John Conlisk, an economist from the University of California at San Diego, later analyzed those papers and suggested that “some conclusions are too enthusiastic.”

Other results would further discolor the rose-tinted view. Some scientists have found that oxytocin boosts envy and schadenfreude, as well as favoritism toward one’s own clique. In one experiment, volunteers who played a game with people they knew were more cooperative after a noseful of oxytocin, while those who played with anonymous strangers became less cooperative.