The study, published in the Journal of Personality and Social Psychology, found that women feel more relaxed after being exposed to their partner’s scent. An experiment including 96 couples shed light on why this phenomenon occurs.
Men were given clean shirts, which had to be worn for 24 hours. They were forbidden to use deodorant and household scented toiletries. They also had to refrain from smoking and eating fragrant food. After 24 hours their shirts were frozen for best scent preservation.
The women were then randomly picked to smell a T-shirt that had been worn by their partner or a stranger. They were unaware which ones they had been given.
The ladies then had to answer questions about their stress levels and were asked to give saliva samples in order to measure their cortisol levels, which is a stress hormone.
The results showed that women who had smelled the shirts worn by their romantic partners felt less stressed both before and after the stress test. These women also had lower levels of cortisol.
Meanwhile, women who had smelled a stranger's scent had higher cortisol levels throughout the stress test.
This experiment demonstrated that smelling a familiar scent of a loved one reduces levels of stress in women.
The researchers behind the experiment also suggested that evolutionary factors could influence why the stranger's scent affected cortisol levels.
"From a young age, humans fear strangers, especially strange males, so it is possible that a strange male scent triggers the 'fight or flight' response that leads to elevated cortisol," Marlise Hofer, the study's lead author said. "This could happen without us being fully aware of it," she added.