And the makers of the new testosterone gel, which will be marketed in the U.S. come summer, couldn't have asked for better publicity. The only thing the public are getting is confusion. Social circumstances remain far more important. Sullivan was careful to state that most of his claims were based on speculation and personal experience - but he did cite a variety of researchers as well, some of whom later wrote to the Times claiming he had exaggerated their conclusions. However, while the environment may stimulate increases in testosterone, it never does so in women to the extent that it does in men, a fact that the cultural explanation cannot account for.
Studies find that extremes of the hormone, either extremely high or low, can lead to depression.
In people with HIV, testosterone levels fall and studies find that adding the hormone back can decrease wasting, improve mood and return a general sense of well-being and energy. Testosterone also clearly increases sex drive amongst both genders. Interpretations of the rest of the data are more difficult. For example, Sullivan believes that testosterone gives men a competitive edge in business because it is has been linked with risk-taking. He even suggests that women might take testosterone to level the playing field.