The next time you’re feeling tense, skip the hot bubble bath and instead head straight for the nearest sweaty male.

New research from George Preti and Charles Wysocki, adjunct professors in the Departments of Dermatology and Animal Biology respectively, has shown that women who sniff male underarm secretions feel more relaxed and less tense. Their findings, which will appear in a forthcoming issue of Biology of Reproduction, also showed that the length and timing of a woman’s menstrual cycle are altered by a whiff of that smelly stuff.

In their study, 18 women, ranging from 25 to 45 years old, were exposed to two different extracts. Half of the group received extracts taken from the armpits of male volunteers in the first half of the exposure period, which lasted a total of 12 hours, while the other half received the control solution first. Participants were not told what they would be smelling.

“When you put [the extracts] under the nose like that, you could not tell them apart,” said Preti. “Most people said alcohol, perfume and some people even say lemon floor wax.”

Twice in each six-hour period, participants were asked to rate on a particular scale how they felt. Much to the surprise of the researchers, who were conducting the tests in a sterile laboratory—not the most comfortable environment—the women reported feeling more at ease after exposure to the perspiration.

Blood analyses further revealed that smelling the male secretions affected the release of the women’s luteinizing hormone (LH), which is produced by the pituitary gland in a pulsing fashion. Changes in LH reflect the release of gonadotropin releasing hormone (GnRH) from the brain’s hypothalamus. GnRH’s positive influence on LH alters the length and timing of the menstrual cycle, which, in turn, affects fertility.

According to the Monell Chemical Senses Center researchers, the effects arise from exposure to pheromones that are produced in the underarm. While pheromones are widely recognized as sexual attractants, Wysocki explained that these chemicals can be seen more broadly. Preti and Wysocki report that two types of pheromones—modulator pheromones, which appear to alter mood, and primer pheromones, which affect physiology—are at play. Because sweat is a complex mixture of substances, it’s difficult to say whether one or more chemicals are responsible for the changes.

Thus comes the next challenge for the researchers—identifying the causative compounds. Wysocki described it as an ever-more-refined process of fractionating and testing the sweat mixture.

Wysocki’s and Preti’s finding is hopeful news for those trying to optimize their chances of conceiving. There’s also a broader segment of the population that stands to benefit. Women may one day be able to treat their pre-menstrual syndrome via a nasal spray. But don’t get too excited just yet; Preti said such clinical applications are “a long way down the road.”