Feeling all warm and fuzzy? Chalk it up to oxytocin, the touchy-feely hormone that enables mothers to bond with their babies (thus the nickname the “cuddle chemical”). Oxytocin fluctuates throughout our lives—during and after childbirth, as well as when you’re sexually aroused or reach the big O. But this feel-good chemical may have a surprising dark side, according to research published in the August issue of the journal Current Directions in Psychological Science.

Rather than oxytocin making them feel like they were in the “trust tree” singing “Kumbaya,” study subjects given the chemical before playing a game of chance exhibited more gloating and envy of their opponents. According to the study co-author Andrew Kemp, Ph.D., of the University of Sydney, the new theory behind oxytocin is that it’s not necessarily about booting positive social emotions, but rather the chemical may increase the so-called approach-related emotions. These are feelings that have to do with wanting something, which can skew positive—into generosity and altruism—or negative—into envy and gloating.

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In other words, being high in oxytocin doesn’t automatically make you high on life or more trusting. People who experience a surge of the chemical may feel more—for better or for worse. And how you’ll feel on oxytocin is unpredictable and depends on the situation. “The point is not that oxytocin elicits contradictory feelings,” says Kemp. “Rather the point is that oxytocin does not always enhance positive emotions. Approach-related, negative emotions such as anger, envy and gloating may also be facilitated.”

(So caveat emptor when a Web ad for a company’s oxytocin nasal spray pops up on your computer screen promising that you can “unleash the power of liquid trust!” to “become instantly irresistible.”)

Given that, oxytocin therapy may not be the feel-good solution for all of our ills—from anger management to clinical depression. The hormone has been studied as a treatment for those with generalized anxiety disorder (GAD) and borderline personality disorder. While preliminary results showed the GAD patients as being less likely to socially withdraw, Kemp says, “Surprisingly, results reported for borderline patients indicated that oxytocin may actually decrease—not increase—trust.”

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The upside? If you’ve got high levels of oxytocin coursing through your veins, that doesn’t mean you’ll toss good judgment out the window and trust just anyone. “Recent studies suggest that oxytocin does not increase ‘blind’ trust and that individuals on oxytocin are able to discriminate between good and bad outcomes,” says Kemp.