The secret allure of the armpit

Pleasant odour is released during women's fertile phase to attract males

Exotic perfumes and colognes have long played a central role in romance, but new research suggests that none may be as powerful as the scent of a woman herself.

At certain times of the month, the female armpit releases a more pleasant odour designed to appeal to the passing male nostril, according to the research.

With the help of samples of underarm odours, and a panel of male volunteers, academics have, for the first time, been able to show that during the fertile phase of her menstrual cycle, a woman's body odour becomes more attractive.

The changing hormones may alter the body odour so that women can - unwittingly - signal their fertility, researchers say.

Separate studies suggest a woman's genetic heritage may also affect her body odour, leading researchers to conclude that BO may help humans select a genetically compatible mate.

Scientists examined variations of axillary, or armpit, odour across the menstrual cycle, in the latest research, to see whether or not women give off signals of their fertility.

Jan Havlek, an anthropologist at Charles University in Prague who led the study, said that females in a number of primate species signal that they are fertile with behavioural or physical changes. "Traditionally, the fertile period in human females has been considered to be concealed, but this presumption has rarely been tested," he said.

"Our results suggest that men can potentially use axillary smell as a mechanism for monitoring menstrual cycle phase in ... sexual partners."

Twelve women wore cotton pads in their armpits for 24 hours at a time. These were sniffed by 42 male volunteers aged between 19 and 34. The men's rating show a correlation across the month between the women's fertility and their attractiveness.