German researchers found that men in monogamous relationships who were given an oxytocinnasal spray stayed about four to six inches farther away from an attractive, woman they didn't know, compared with men in monogamous relationships who received a placebo.
The oxytocin spray had no effect on the distance that single men chose to keep between themselves and the attractive woman, MyHealthNewsDaily reported.
"The results suggest the hormone promotes fidelity in humans," said study researcher Dr Rene Hurle