A new study has shown that a woman's natural smell sends the male testosterone soaring - especially when they are ovulating.
Smells are known to be critical to animal mating habits, as various studies have shown that male testosterone levels are influenced by odour signals emitted by females, particularly when they are ovulating (that is, when they are the most fertile). In the new study, conducted by psychological scientists Saul L. Miller and Jon K. Maner from Florida State University, women wore tee shirts for 3 nights during various phases of their menstrual cycles. Male volunteers smelled one of the tee shirts that had been worn by a female participant.
In addition, some of the male volunteers smelled control tee shirts that had not been worn by anyone. Saliva samples for testosterone analysis were collected before and after the men smelled the shirts. They found that men who smelled tee shirts of ovulating women subsequently had higher levels of testosterone. Men found the shirts worn by ovulating women most pleasant smelling.
The authors noted, "The present research is the first to provide direct evidence that olfactory cues to female ovulation influence biological responses in men." The study suggests that testosterone levels may be responsive to smells indicating when a woman is fertile. The authors conclude that this biological response may promote mating-related behaviour by males.