Other drugs already on the market also lower testosterone levels, but not without sometimes raising them first.
It is not enough to simply lower testosterone levels after diagnosing an athlete's disorder, she said.
But, he added, "each of those manipulations -- excesses of diet, exercise and alcohol, as well as sleep deprivation -- can lower testosterone levels".
Sara S. Strom, the lead author of the study and an associate professor at the University of Texas, said scientific evidence suggested that obesity was linked to lower testosterone levels and higher insulin levels.
'A recent study, in fact, reported that men with lower testosterone levels were more likely to get heart disease, and while prostate cancer is sensitive to testosterone, the hormone has not been shown to be a direct cause,' he states.
"The observations could make some evolutionary sense if we accept the idea that men with lower testosterone levels are more likely to be monogamous with their partner and care for children.
Women, with their lower testosterone levels, end up with a smaller proportion of Type 2 muscle fibers, which are used to generate speed and power and strength, Tarnopolsky said.
Some experts have questioned whether soy might lower testosterone levels in men and cause problems for women who have estrogen-sensitive breast cancers.
Moreover, lower testosterone levels in working boys, due to delayed puberty, may result in suppression of somatotropic axis.
All of these changes tend to make male faces look more like female ones, Franciscus noted at the meeting, and are linked to lower testosterone levels.
A review of some of the current biomedical therapies for autistics, such as glutathione and cysteine, chelation, secretin, and growth hormone, suggests that they may in fact lower testosterone levels.
