March 19, 2003 -- The scent of a good man may be music to a woman's nose. Researchers say the odorless pheromones found in male perspiration can have a dramatic effect on both a woman's mind and body. A new study found exposure to male pheromones can boost a woman's mood and stimulate the release of a hormone that regulates the menstrual cycle.

In the study, researchers applied extracts of underarm secretions from male volunteers to the upper lips of 18 women between the ages of 25 and 45. None of the women knew that male sweat had been applied to their lips, and some thought they were involved in a study of alcohol or perfume or even lemon floor wax. The women then rated their moods over six hours of exposure; they consistently reported feeling less tension and more relaxed.

"Much to our surprise, the women reported feeling less tense and more relaxed during exposure to the male extract," says researcher Charles J. Wysocki of the University of Pennsylvania, in a news release. "This suggests that there may be much more going on in social settings like singles bars than meets the eye."

Each of the women received three applications of the underarm extract during the six-hour evaluation period, followed by three doses of exposure to ethanol (alcohol) over another six-hour period.

Researchers also found that exposure to the male pheromones also prompted a shift in blood levels of a reproductive hormone called luteinizing hormone. Levels of this hormone typically surge before ovulation, but women also experience small surges during other times in the menstrual cycle.

The study found that the male pheromone extract hastened the onset of these smaller surges and shortened the pauses between surges by 20%.

Researchers are now looking at individual compound that are found in male perspiration in hopes of identifying the elements responsible for these psychological and hormonal changes.

"This may open the door to pharmacological approaches to manage onset of ovulation or the effects of premenstrual syndrome or even natural products to aid relaxation," says Wysocki. "By determining how pheromones impact mood and endocrine response, we might be able to build a better male odor: molecules that more effectively manipulate the effects we observed."

SOURCE: Biology of Reproduction, June 2003. News release, University of Pennsylvania.