News Release

First-ever study reveals smell of sweat may alter how women are judged

Monell Chemical Senses Center partners with P&G's SecretTM brand to evaluate stress sweat and its impact on perception of confidence, trustworthiness and competence

Peer-Reviewed Publication

Spectrum Science

(Cincinnati, OH) - Today, a new study from P&G Beauty, the makers of SecretTM deodorants, and lead investigator Pamela Dalton, PhD. MPH, member of the Monell Chemical Senses Center, confirms for the first time that the smell of stress sweat does, in fact, significantly alter how women are perceived by both males and females. Results of the study, published on October 9, 2013 in PLOS ONE, indicate that the odor from stress-related sweat specifically impacts social judgments of one's confidence, trustworthiness and competence.

The ability of human body odor to communicate information between individuals is supported by an ever-expanding body of research. Not only have body odor signals been shown to convey messages about genetic connection, dating and general health, but body odors produced from individuals in specific emotional states have been shown to affect both the neural and behavioral states of the receiver, whether or not they are consciously aware of the source of the body odor.

"Stress-induced sweat, the worst smelling of the three causes of sweat, can occur unexpectedly at any point in the day, often becoming a vicious cycle. Research demonstrates there are three causes of sweat: physical exertion, environmental heat and stress. Sweat caused by physical activity (internal thermal stress) and environmental heat (external thermal stress) are produced by secretions from the eccrine sweat gland, while stress (emotional) sweat is produced by secretions from the eccrine and apocrine gland." said Dr. Susan Biehle-Hulette, Procter & Gamble and Secret brand senior scientist for product development, "and as this sweat mixes with bacteria on our skin, the result is a distinguishably foul odor."

Researchers sampled 44 female donors who provided three types of axillary odor samples including; exercise sweat, stress sweat (untreated) and stress sweat (treated with Secret Clinical StrengthTM).

Study Methodology

Participants wore comfortable clothes for exercising that would allow access to the underarm for sample collection, and were seated in a climate-controlled chamber where baseline recordings of heart rate and mood were obtained.

A different experimenter then administered the Trier Social Stress Test (TSST) which was comprised of:

  • Five minutes of speech preparation
  • Five minutes of mental arithmetic
  • Five minutes of public speaking

After the TSST, participants were asked to fill out the mood ratings and sweat samples were obtained. The participants were then informed they would exercise on a stationary cycle for 15 minutes and sweat samples would be collected as well as mood ratings.

Once the test was completed, 120 male and female evaluators, presented with samples of each type of sweat, watched videos of women performing every-day activities (office, home, childcare, etc.) in order to rate how stressed each woman appeared. All evaluators rated the females with treated stress sweat as significantly more confident (p=.02), trustworthy (p=.03) and competent (p=.048).


Women evaluated in the presence of untreated stress sweat were equally rated by males and females as 'stressed.' In addition, male evaluators rated the women in the videos significantly less confident, competent and trustworthy when the videos were paired with the untreated stress sweat.

"Researchers have studied the impact of stress sweat on emotional states and brain activity, but we have not previously evaluated how it influences social perception," said Dr. Dalton. "For the first time, we have found that stress sweat odor impacts overall judgments of perceived confidence, trustworthiness and competence."

This year, Procter & Gamble's Secret brand launched its "Stress Stinks" marketing campaign to reach women worried about stress-induced sweat. P&G's patented odor-neutralizing technology, contained in its Secret Clinical Strength TM antiperspirant has been proven in clinical studies (results were shared at this year's American Academy of Dermatology meeting) to effectively fight all three causes of sweat.

"Secret is a brand committed to helping women confidently face whatever life throws at them," said John Sebastian, Marketing Director, P&G Beauty. "Whether she's a business woman delivering a presentation, a mom confronting her child's principal or a college student about to give her first public speech, these new findings about stress sweat underscore the importance confidence plays, giving us even more reasons to believe our Secret Clinical StrengthTM products are precisely what women need to face any stressful situation. We believe this news is relevant for a lot of women."


About Procter & Gamble

P&G serves approximately 4.8 billion people around the world with its brands. The Company has one of the strongest portfolios of trusted, quality, leadership brands, including Ace®, Always®, Ambi Pur®, Ariel®, Bounty®, Charmin®, Crest®, Dawn®, Downy®, Duracell®, Fairy®, Febreze®, Fusion®, Gain®, Gillette®, Head & Shoulders®, Iams®, Lenor®, Mach3®, Olay®, Oral-B®, Pampers®, Pantene®, Prestobarba®, SK-II®, Tide®, Vicks®, Wella®, and Whisper®. The P&G community includes operations in approximately 70 countries worldwide. Please visit for the latest news and in-depth information about P&G and its brands.

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