One implication of the finding is that there may be better ways to raise cortisol levels in patients with diseases such as Addison's disease, which is characterized by low cortisol. Instead of giving the hormone in pill form, which has side effects such as ulcers and weight gain, "a potential therapeutic mechanism whereby merely smelling synthesized or purified human chemosignals may be used to modify endocrine balance," the authors wrote.

Sweat has been the main focus of research on human pheromones, and in fact, male underarm sweat has been shown to improve women's moods and affect their secretion of luteinizing hormone, which is normally involved in stimulating ovulation. Other studies have shown that when female sweat is applied to the upper lip of other women, these women respond by shifting their menstrual cycles toward synchrony with the cycle of the woman from whom the sweat was obtained.

Androstadienone, a derivative of testosterone that is found in high concentration in male sweat, and in all other body secretions, has garnered the most attention. However, though its effect on a woman's mood, physiological arousal and brain activity suggests that the chemical is a possible pheromone-like signal in humans, its effect on hormone levels was unknown.

Wyart and Sobel set out to test whether androstadienone affects hormone levels as well, focusing on the hormone cortisol. Cortisol is secreted by the body in times of stress, priming the body for "fight or flight."

In two trials, a total of 48 undergraduate women at UC Berkeley were asked to take 20 sniffs from a bottle containing androstadienone, which smells vaguely musky. Over a period of two hours, the volunteers provided five saliva samples from which cortisol levels were determined.

Compared to their response when sniffing a c
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Contact: Robert Sanders
rsanders@berkeley.edu
510-643-6998
University of California - Berkeley
6-Feb-2007