Well, it’s not a love potion so much as a nasal spray but researchers found that men in relationships who take a dose of oxytocin – a hormone that promotes bonding – were more likely to become uncomfortable at the advances of another woman. Here’s how they proved it:

The research team singled out the most attractive female among them to approach their male subjects. Each of the 57 men had been administered either oxytocin or a placebo via nasal spray prior to the encounter. The attractive researcher would stand about 24 inches away from the subject, and then move toward and away from them. The men were asked to determine when the attractive researcher was at an “ideal distance” and when she got too close, making them feel “slightly uncomfortable.”

The men confirmed after the experiment was completed that the attractive researcher was, in fact, attractive.

The men who got oxytocin preferred a distance of 4 to 6 inches further than those who got the placebo. The study also showed that the men who got the actual “love drug” didn’t find the woman research less attractive; they were uncomfortable when she got too close.