Featured Research

from universities, journals, and other organizations

Male Sweat Boosts Women's Hormone Levels

Date:
February 8, 2007
Source:
University of California - Berkeley
Summary:
Male sweat, and one particular chemical in male sweat, is known to influence women's moods, and even increase their sexual arousal. Now, a study by Claire Wyart at UC Berkeley shows that the chemical andrastadienone in male sweat also boosts levels of the hormone cortisol in women who sniff it. These findings suggest that andrastadienone may be a human pheromone, causing both behavioral and hormonal changes in women.

Just a few whiffs of a chemical found in male sweat is enough to raise levels of the stress hormone cortisol in heterosexual women, according to a new study by University of California, Berkeley, scientists.

The study, reported this week in The Journal of Neuroscience, provides the first direct evidence that humans, like rats, moths and butterflies, secrete a scent that affects the physiology of the opposite sex.

"This is the first time anyone has demonstrated that a change in women's hormonal levels is induced by sniffing an identified compound of male sweat," as opposed to applying a chemical to the upper lip, said study leader Claire Wyart, a post-doctoral fellow at UC Berkeley.

The team's work was inspired by previous studies by Wyart's colleague Noam Sobel, associate professor of psychology at UC Berkeley and director of the Berkeley Olfactory Research Program. He found that the chemical androstadienone - a compound found in male sweat and an additive in perfumes and colognes - changed mood, sexual arousal, physiological arousal and brain activation in women.

Yet, contrary to perfume company advertisements, there is no hard evidence that humans respond to the smell of androstadienone or any other chemical in a subliminal or instinctual way similar to the way many mammals and even insects respond to pheromones, Wyart said. Though some humans exhibit a small patch inside their nose resembling the vomeronasal organ in rats that detects pheromones, it appears to be vestigial, with no nerve connection to the brain.

"Pheromones are chemical molecules expressed by a species aimed at other members of the species to induce stereotyped behavior or hormonal changes," Wyart explained. "Many people argue that human pheromones don't exist, because humans don't exhibit stereotyped behavior. Nonetheless, this male chemical signal, androstadienone, does cause hormonal as well as physiological and psychological changes in women. More cognitive studies need to be done to understand how androstadienone affects female cognitive functions."

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 control odor (yeast), the women who sniffed androstadienone reported an improved mood and significantly higher sexual arousal, while their physiological response, including blood pressure, heart rate and breathing, also increased. This was consistent with previous studies.

In addition, however, the UC Berkeley researchers found that cortisol levels rose within about 15 minutes of sniffing androstadienone, and remained elevated for more than an hour.

Wyart noted that, though this is the first time a specific component of male sweat has been shown to affect women's hormones, other constituents of male sweat likely have a similar effect. The question remains: Which comes first - the change in cortisol level, which may induce a change in mood or arousal; or a mood change that increases cortisol levels?

"We next need to look at other hormones that could explain the diversity of effects of androstadienone on sexual arousal and mood," she said.

Coauthors of the report include UC Berkeley undergraduates Sarah Wilson, Jonathan Chen and Andrew McClary; senior scientist Rehan Khan; and Dr. Wallace Webster, an otolaryngology resident at Kaiser Permanente Hospital in Oakland, Calif. The work was sponsored by the National Institute on Deafness and Other Communicable Disorders of the National Institutes of Health, and by the Army Office of Research.


Story Source:

The above story is based on materials provided by University of California - Berkeley. Note: Materials may be edited for content and length.


Cite This Page:

University of California - Berkeley. "Male Sweat Boosts Women's Hormone Levels." ScienceDaily. ScienceDaily, 8 February 2007. <www.sciencedaily.com/releases/2007/02/070207172019.htm>.
University of California - Berkeley. (2007, February 8). Male Sweat Boosts Women's Hormone Levels. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2007/02/070207172019.htm
University of California - Berkeley. "Male Sweat Boosts Women's Hormone Levels." ScienceDaily. www.sciencedaily.com/releases/2007/02/070207172019.htm (accessed July 31, 2014).

Share This




More Health & Medicine News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Health Insurers' Profits Slide

Health Insurers' Profits Slide

Reuters - Business Video Online (July 30, 2014) Obamacare-related costs were said to be behind the profit plunge at Wellpoint and Humana, but Wellpoint sees the new exchanges boosting its earnings for the full year. Fred Katayama reports. Video provided by Reuters
Powered by NewsLook.com
Concern Grows Over Worsening Ebola Crisis

Concern Grows Over Worsening Ebola Crisis

AFP (July 30, 2014) Pan-African airline ASKY has suspended all flights to and from the capitals of Liberia and Sierra Leone amid the worsening Ebola health crisis, which has so far caused 672 deaths in Guinea, Liberia and Sierra Leone. Duration: 00:43 Video provided by AFP
Powered by NewsLook.com
At Least 20 Chikungunya Cases in New Jersey

At Least 20 Chikungunya Cases in New Jersey

AP (July 30, 2014) At least 20 New Jersey residents have tested positive for chikungunya, a mosquito-borne virus that has spread through the Caribbean. (July 30) Video provided by AP
Powered by NewsLook.com
Xtreme Eating: Your Daily Caloric Intake All On One Plate

Xtreme Eating: Your Daily Caloric Intake All On One Plate

Newsy (July 30, 2014) The Center for Science in the Public Interest released its 2014 list of single meals with whopping calorie counts. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



    Save/Print:
    Share:

    Free Subscriptions


    Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

    Get Social & Mobile


    Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

    Have Feedback?


    Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
    Mobile: iPhone Android Web
    Follow: Facebook Twitter Google+
    Subscribe: RSS Feeds Email Newsletters
    Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins