Women Sniff Out Biologically-Relevant Information
From Underarm Sweat
It may be wise to trust the female nose when it comes to body odor.
According to new research from the Monell Center, it is more difficult
to mask underarm odor when women are doing the smelling.
"It is quite difficult to block a woman's awareness of
body odor. In contrast, it seems rather easy to do so in men,"
said study lead author Charles J. Wysocki, PhD, a behavioral neuroscientist
The researchers speculate that females are more attuned to biologically
relevant information in sweat that may guide women when choosing
In the study, women and men rated the strength of underarm odors,
both alone and in conjunction with various fragrances.
The fragrances were selected to test their ability to block underarm
odor through a method known as cross-adaptation. Olfactory adaptation
refers to the loss of sensitivity to an odor when one is constantly
exposed to that odor. Olfactory cross-adaptation occurs when the
nose adapts to one odor and then also becomes less sensitive to
a second odor.
Sniffed alone, the underarm odors smelled equally strong to men
and women. When fragrance was introduced, only two of 32 scents
successfully blocked underarm odor when women were doing the smelling;
in contrast, 19 fragrances significantly reduced the strength
of underarm odor for men.
Wysocki noted that in earlier studies, men and women did not
differ in their ability to cross-adapt to odors not from the body.
"Taken together, our studies indicate that human sweat conveys
information that is of particular importance to females. This
may explain why it is so difficult to block women's perception
of sweat odors," he said.
Not only were women better smellers the men, but male odors were
harder to block than female odors. Even though underarm odors
from the two sexes didn't differ in how strong they smelled, only
19 percent of the fragrances successfully reduced the strength
of male underarm odor; in contrast, over 50 percent decreased
intensity of female underarm odor.
In the study, one sensory panel evaluated fragrances for their
ability to counteract female underarm odor; a second panel judged
the effectiveness of fragrances against male odor. Each panel
contained both men and women.
To make their odor evaluations, panelists sniffed vials of underarm
sweat previously collected in the laboratory from volunteers.
Panelists first rated the intensity of underarm odor to provide
a measure of the odor's strength. They then continued to rate
underarm odor intensity while sniffing a fragrance for 2-1/2 minutes.
A drop in intensity ratings for the underarm odor indicated that
the fragrance was a successful cross-adapting agent, capable of
neutralizing the odor.
"Men and women differ in how they perceive body odors from
both their own and the opposite sex," summarized Monell scientist
George Preti, PhD, an analytical organic chemist who co-led the
research with Wysocki. "Women are more aware of underarm
odor and they appear to be detecting differences in odor quality."