Women looking for that special someone might want to think twice before
spritzing Chanel No. 5. A new study suggests that a woman's natural scent
may be all she needs.
Recent research shows that a man's testosterone levels, which are linked
with sexual interest, are significantly higher when they smell the shirt of
a woman who is ovulating. These findings could lead to the development of
new fragrances that mimic this effect, and answer basic questions about
"This is an issue that has been hotly debated: whether or not ovulation is
concealed in human females," said Jon Maner, a co-author of the recent paper
in Psychological Science. "In lots of other species, there are very obvious
indicators, but it has long been assumed that human females didn't give off
Over the last 10 years, however, psychologists have found that ovulating
women may behave differently, with a tendency to be more flirtatious, have
sexual fantasies more frequently, and prefer hyper-masculine men.
In surveys, men report being more attracted to ovulating women. The new
study builds on this research by measuring the response of men to a specific
The researchers performed two separate but related experiments. In the first
scenario, the scientists gave four women plain, white T-shirts. The women
wore the shirts over three days when they went to sleep. The researchers
then collected the shirts in plastic bags, divided them up according to
whether the woman was ovulating, and froze them.
In the second experiment, the scientists added an extra variable: fresh
T-shirts that hadn't been worn by anyone.
T-shirts in hand, the scientists asked dozens of men to stick their noses
into the bags. As the men sniffed the shirts, scientists sampled the
participants' saliva, which was used to measure testosterone.
Men who smelled the shirts of ovulating women in the first experiment had,
on average, testosterone levels that were 37 percent higher than the men who
smelled the shirts of non-ovulating women.
For the second experiment, the testosterone levels of the men who smelled
the T-shirts of ovulating women were, on average, 15 percent higher than men
who sniffed the two other T-shirt samples.
Other studies have linked higher levels of testosterone with an increased in
sexual arousal, said Maner. Whether a 37 percent or 15 percent difference in
testosterone is enough to affect a man's behavior is unknown.
Another unknown is the whether a man could detect an ovulating women in a
real-world situation, say a crowded bar. The two experiments were done under
controlled laboratory conditions. Nevertheless, scientists say the
experiments could have real world significance for potential love
"The men were smelling T-shirts, not real women," said Maner. "We would
expect that the odor coming from a woman will be stronger than from a
T-shirt that was frozen."
Exactly how far the odor diffuses away from a woman remains to be seen.
Scientists also haven't identified the specific chemical scents that
stimulate increases in testosterone levels in men.
It's possible that men are directly detecting the higher levels of estrogen
during ovulation, said Jim Roney, a scientist at the University of
California, Santa Barbara. Equally possible is that men are sensing other
chemicals that rise and fall depending on the amount of estrogen. Scientists
just don't know.
Despite the remaining unknowns, the new research marks a milestone for smell
"This is one of the first papers to show (a change in testosterone) in
response to a chemical stimulus," said Roney. "It's a new area of research."